Highway Traffic Monitoring SystemSenior Design May05-06

System Proposal

ClientIowa State University

Faculty AdvisorsProfessor John Lamont

Professor Ralph Patterson III

Duane E. Smith, P.E., Associate Director for Outreach, CTRE

Team MembersBen Armfield, CprE

Joel Cardo, CprE

Wendell Cotton, EE

Brent Duppong, EE

REPORT DISCLAIMER NOTICE

DISCLAIMER: This document was developed as a part of the requirements of an electrical and computer engineering course at Iowa State University, Ames, Iowa. This

document does not constitute a professional engineering design or a professional land surveying document. Although the information is intended to be accurate, the associated

students, faculty, and Iowa State University make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of

this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting

from this student-prepared document that is required to be under the responsible charge of a licensed engineer or surveyor. This document is copyrighted by the students who

produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

April 5, 2005

Table of Contents

List of Figures................................................................................................................v

List of Tables................................................................................................................vii

List of Definitions........................................................................................................viii

Section 1 – Introductory Materials................................................................................1

1.1 Executive Summary.........................................................................................1

1.2 Acknowledgement...........................................................................................2

1.3 Problem Statement..........................................................................................31.3.1 General Problem Statement.....................................................................31.3.2 General Solution Approach.....................................................................4

1.4 Operating Environment...................................................................................6

1.5 Intended Users and Uses................................................................................71.5.1 Intended Users..........................................................................................71.5.2 Intended Uses...........................................................................................8

1.6 Assumptions and Limitations.........................................................................81.6.1 Initial Assumptions List...........................................................................81.6.2 Initial Limitations List...............................................................................8

1.7 Expected End Product and Other Deliverables............................................9

Section 2 - Overall System Design and Layout.........................................................11

2.1 Approach Used and Progress Results........................................................112.1.1 Design Objectives...................................................................................112.1.2 Functional Requirement.........................................................................122.1.3 Design Constraints.................................................................................12

2.2 System Layout...............................................................................................142.2.1 Component Layout.................................................................................142.2.2 Location Adaptability.............................................................................16

2.3 System Flow...................................................................................................19

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Section 3 - Component Design...................................................................................21

3.1 Sensor System...............................................................................................213.1.1 Sensor System Overview.......................................................................213.1.2 Sensor System Evaluation.....................................................................223.1.3 Sensor System Selection.......................................................................22

3.2 Control System..............................................................................................243.2.1 Control System Overview......................................................................243.2.2 Control System Evaluation....................................................................253.2.3 Control System Selection......................................................................25

3.3 Communication System................................................................................273.3.1 Communication System Overview........................................................273.3.2 Communication System Evaluation......................................................273.3.3 Communication System Selection........................................................28

3.4 Display System..............................................................................................293.4.1 Display System Overview......................................................................293.4.2 Display System Evaluation....................................................................293.4.3 Display System Selection......................................................................30

3.5 Combined Communication and Display Option..........................................32

Section 4 - System Construction, Setup, Operation, and Comparison...................34

4.1 System Construction.....................................................................................34

4.2 System Setup.................................................................................................37

4.3 System Operation..........................................................................................38

4.4 Complete System Comparison.....................................................................394.4.1 Complete System Overview...................................................................394.4.2 Complete System Evaluation and Recommendation..........................40

Section 5 - Closure Material........................................................................................42

5.1 Project Team Information..............................................................................425.1.1 Client........................................................................................................42

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5.1.2 Faculty Advisors.....................................................................................425.1.3 Student Team Information.....................................................................435.1.4 Project Website.......................................................................................43

5.2 Closing Summary..........................................................................................44

5.3 References.....................................................................................................45

Appendix A - Overall System Layout and Design.....................................................46

A.1 Flow Charts....................................................................................................46

A.2 Traffic Condition List.....................................................................................51

A.3 PLC Ladder Code...........................................................................................52

A.4 Complete Parts List for Highway Exit Monitoring System.........................56

Appendix B - Sensor System......................................................................................57

B.1 Sensor Technology Evaluation....................................................................57B.1.1 Sensor Technology Criteria Identification............................................57B.1.2 Sensor Technology Identification and Research.................................59

B.2 Datasheet........................................................................................................79B.2.1 IFM Efector Cable...................................................................................79B.2.2 IFM Efector Installation Instructions.....................................................80B.2.3 IFM Efector Reflector..............................................................................81B.2.4 IFM Efector Sensor.................................................................................82

Appendix C - Control System......................................................................................83

C.1 PC-Based Control Technology Evaluation..................................................83C.1.1 PC-Based Control Technology Criteria Identification.........................83C.1.2 PC-Based Control Technology Identification and Research..............85C.1.3 PC-Based Control Technology Selection...........................................104

C.2 PLC-Based Control Technology Evaluation..............................................105C.2.1 PLC-Based Control Technology Criteria Identification.....................105C.2.2 PLC-Based Control Technology Identification and Research..........107

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C.3 Datasheet......................................................................................................112C.3.1 Allen Bradley MicroLogix 1000 PLC...................................................112C.3.2 GE Fanuc Nano and Micro PLC’s........................................................114C.3.3 Mitsubishi Alpha...................................................................................117

Appendix D - Communication System.....................................................................119

D.1 Communication Technology Evaluation...................................................119D.1.1 Communication Technology Criteria Identification...........................119D.1.2 Communication Technology Identification and Research................121

D.2 Datasheet......................................................................................................126D.2.1 Encom7318............................................................................................126D.2.2 Remote Control Tech Wireless Switching System............................128

Appendix E - Display System....................................................................................130

E.1 Display Technology Evaluation..................................................................130E.1.1 Display Technology Criteria Identification.........................................130E.1.2 Display Technology Identification and Research..............................132

E.2 Datasheet......................................................................................................138E.2.1 OkSolar Flashing Light System...........................................................138E.2.2 Highway Information Systems Radio Broadcaster............................140E.2.3 National Signal Portable Message Board...........................................142

Appendix F - System Construction, Setup, and Operation....................................143

F.1 Diagnostic Testing Procedure....................................................................143

F.2 Complete System Comparison...................................................................144F.2.1 Complete System Criteria Identification.............................................144F.2.2 Complete System Identification and Research..................................145

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List of Figures

Figure 1 - Diagram of basic process flow....................................................................1Figure 2 - Map of the primary exit to be examined......................................................4Figure 3 - Layout of system..........................................................................................5Figure 4 - West bound traffic approaching the Elwood Drive Exit 146.....................6Figure 5 - Exit 146, the primary location for system equipment................................7Figure 6 - Overhead detection system layout diagram.............................................15Figure 7 - Medium-speed ramp placement (Elwood Exit off HWY 30 West)...........16Figure 8 - High-speed ramp placement (HWY 30 West Exit off I-35 South)............17Figure 9 - Low-speed ramp placement (HWY 30 West Exit off I-35 North)..............18Figure 10 - Selected infrared reflective light beam sensor.......................................23Figure 11 - Allen Bradley MicroLogix 1000 PLC........................................................26Figure 12 - Encom wireless communication system................................................28Figure 13 - OkSolar warning sign with flashing light................................................32Figure 14 - OkSolar communication system transmitter..........................................32Figure 15 - Inside view of main enclosure with dimensions....................................34Figure 16 - Front view of main enclosure with descriptions....................................35Figure 17 - High level flow diagram of the control logic...........................................46Figure 18 - Flow diagram for system reset................................................................46Figure 19 - Flow diagram of traffic detection.............................................................47Figure 20 - Flow diagram for determining traffic speed...........................................48Figure 21 - Flow diagram for displaying a message.................................................49Figure 22 - Flow diagram for detecting a blocked sensor........................................50Figure 23 - Example of a radar gun with serial output..............................................59Figure 24 - Weather resistant camera mounting option...........................................62Figure 25 - Example of a concrete strain gauge........................................................64Figure 26 - Example of an in-ground wire loops.......................................................67Figure 27 - Example of a temporary on-road loop....................................................67Figure 28 - Example of a road tube with mounting hardware..................................71Figure 29 - Demonstration of laying road tube inside a flexible road ramp...........71

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Figure 30 - Example of rugged vehicle-axle detecting tape switch.........................74Figure 31 - Example of a rugged light beam sensor.................................................76Figure 32 - Red Hat Linux............................................................................................87Figure 33 - Solaris a UNIX operating system.............................................................88Figure 34 - Microsoft Windows XP Professional.......................................................90Figure 35 - Microsoft Windows Server 2003..............................................................91Figure 36 - Screenshot of Mac OS X...........................................................................93Figure 37 - Mac OS X Server.......................................................................................94Figure 38 - Dell desktop...............................................................................................96Figure 39 - iMac G5......................................................................................................97Figure 40 - Sun Blade 150 workstation......................................................................99Figure 41 - Intermec's CV60......................................................................................101Figure 42 - Gateway laptop.......................................................................................102Figure 43 - Allen Bradley MicroLogix 1000 PLC......................................................107Figure 44 - Mitsubishi Alpha PLC.............................................................................109Figure 45 - GE Fanuc VersaMax Nano......................................................................110Figure 46 - Encom wireless communication system..............................................122Figure 47 - Remote Control Technology transmitter module.................................124Figure 48 - Remote Control Technology receiver module......................................124Figure 49 - Example of a trailer-mounted sign with flashing lights.......................132Figure 50 - Trailer-mounted electronic message board.........................................134Figure 51 - Pole-mounted radio broadcast transmitter..........................................136Figure 52 - Possible radio notification sign.............................................................136Figure 53 - Nu-Metrics magnetic sensor unit..........................................................146Figure 54 - IRD trailer mounted warning sign with flashing lights........................148Figure 55 - Another IRD warning sign with flashing lights............................................148

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List of Tables

Table 1 - Speed adjustment ranges...............................................................................18

Table 2 - Sensor system evaluation overview...........................................................22Table 3 - Evaluation of sensor technologies based on identified criteria...............22Table 4 - PLC-based control system evaluation overview.......................................25Table 5 - Evaluation of PLC control technology based on identified criteria.........25Table 6 - Communication system evaluation overview............................................28Table 7 - Evaluation of communication technology based on identified criteria...28Table 8 - Evaluation of display technology based on identified criteria.................31Table 9 - Wire landing table.........................................................................................36Table 10 - Possible traffic system condition list.......................................................51Table 11 - Address table showing integer time values.............................................55Table 12 - Complete parts list.....................................................................................56Table 13 - Operating system identification................................................................85Table 14 - Non-mobile hardware platform identification..........................................86Table 15 - Mobile hardware platform identification...................................................86Table 16 - Evaluation of software control technologies.........................................104Table 17 - Evaluation of hardware control technologies..............................................104

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List of Definitions

802.11b - A family of specifications developed by the IEEE for wireless LAN technology.

Center for Transportation Research and Education (CTRE) - Performs

transportation research for public and private agencies and companies; manages its

own education program for transportation students; and conducts local, regional,

and national transportation services and continuing education programs.

Code division multiple access (CDMA) (or “spread spectrum”) - A form of

multiplexing where the transmitter encodes the signal using a pseudo-random

sequence which the receiver also knows and can use to decode the received signal.

Each different random sequence corresponds to a different communication channel.

This technology is used for wireless digital data transfer.

Dell - Computer manufacturer that uses Intel processors and comes prepackaged with

Microsoft Windows.

Department of Transportation (DOT) - The United States federal department that

institutes and coordinates national transportation programs; created in 1966.

Groundhog - Magnetic sensor system manufactured by Nu-Metrics that can detect

vehicle length, vehicle speed and road conditions. The system can transmit data

wirelessly via “spread spectrum” technology.

GUI - Graphical user interface, the interface people use when operating a computer to

make using the computer easier.

Highway traffic monitoring system (HTMS) - This name and acronym refer to the

system which the team will be designing.

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Inductive loop - A coil of wire embedded in pavement that detects the change in

inductance when a vehicle drives over it.

Intel - A company that designs and produces microprocessors.

Intermec CV60 - A very rugged computer that is capable of being mounted in a vehicle.

LED - A light emitting diode is an electrical component that emits light.

Light beam - Sensor that detects an object’s presence by detecting the interruption of a

light beam.

Linux - An open source operating system.

Mac – A computer system that runs Mac OS X or Mac OS X Server.

Mac OS X - Macintosh operating system based off of UNIX.

Mac OS X Server - Server based operating system based off of Mac OS X.

Motion detector - Sensor that detects the heat of an object near it. It does this by the

change in infrared light created from the change in heat.

PLC - Programmable logic controller. A device used to automate monitoring and

control of a system. It receives input, performs a series of logical operations, and

provides a signal output.

Radar gun - Sensor that uses radar waves to determine the speed of a vehicle.

RF transmitter/receiver - Radio frequency spectrum transmitter or receiver.

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Road tube - A rubber tube filled with air that detects a vehicle by the change in air

pressure when a vehicle drives over it.

RS232 - Communication standard for signal voltages, signal timing, signal function, a

protocol for information exchange, and mechanical connectors.

Server 2003 - Server operating system based off of Windows and produced by

Microsoft.

Spread spectrum - Refer back to CDMA.

Strain gauge - A sensor that detects weight by measuring the change in resistance of a

metal as it flexes due to the weight of a heavy object.

Sun - Computer company that produces computers that run Linux or UNIX.

Tape switch - A sensor that has two conductive plates separated by a small distance.

When an object presses the plates, they touch together and close the circuit.

UNIX - Operating system similar to Linux except it is not open source.

USB - Stands for universal serial bus and is a connectivity cable that is a standard in

the computer industry.

Windows XP - Operating system that is used on many home computers and is

produced by Microsoft.

Wire loop - Refer back to inductive loop.

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Section 1 – Introductory Materials

The introductory materials section contains the executive summary, acknowledgements,

problem statement, operating environment, intended users and uses, assumptions and

limitations, and expected end-product and other deliverables.

1.1 Executive Summary

The main purpose of this document is to convey to the reader the project goal and the

outcome of the project. The following paragraphs briefly describe what the project is

about and what information is contained in the document.

Traffic accidents often occur when a major athletic event or concert is held at Iowa State

University. This is a result of drivers not being able to observe traffic that is backing up

in hard-to-see locations. The Elwood exit off of west-bound US Highway 30 is one such

example. The objective of this project was to develop a portable system that could

detect slow moving or stopped traffic and then alert approaching drivers. The design

incorporates speed and proximity sensors, a control system, and a display system, see

Figure 1 for an example. The traffic monitoring system was designed to help prevent

such accidents and increase traffic flow during these events. A fully operational system

would be able to save thousands of people travel time, reduce costly vehicle accidents

and possibly save someone's life.

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Figure 1 - Diagram of basic process flow

This document presents a condensed version of the work that has been done in order to

complete the project. A portion of the document covers the research accomplished. In

order to condense the amount of material in this document the detailed selection of the

sensor technology, control systems technology, communications technology, and

warning systems technology, including such important details as to why a specific

technology was selected and how much the technology costs, can be referenced in the

System Proposal Appendix B-E.

The time that has been spent on individual aspects of this design is included, also

contained in this document are the estimated, revised, and actual work hours for

specific tasks that were established at the beginning of the project. Finally, there is a

progress report that details what tasks have been completed and to what future work

could be done.

1.2 Acknowledgement

The design team would like to thank our faculty advisors; John Lamont, Ralph Patterson

and Duane Smith. In addition to our advisors we would also like to thank Willy

Sorenson of the Iowa DOT for his assistance in this project. They have greatly assisted

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the team by donating their time and technical advice. Their support is deeply

appreciated.

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1.3 Problem Statement

The two following sections are a more detailed description of the executive summary

from Section 2.1. The problem will be presented in more detail and the solution

approach will be given.

1.3.1 General Problem Statement

When there are special public events that a large number of people attend, particular

traffic problems occur. For Iowa State University, these events include major sporting

events and large concerts. They often occur at Jack Trice Stadium and at the Iowa

State Center which includes Hilton Coliseum and Stephens Auditorium. All of these

facilities are located off of Elwood Drive.

The problem the team presents a solution for starts before an event begins. There is a

large inflow of traffic to the facilities which causes traffic to slow down and back-up on

Elwood Drive. Because this is the major access road for people coming off of U.S.

Highway 30 (see Figure 2), there is a major safety concern. Vehicles that are traveling

at highway speeds are encountering slow moving or stopped vehicles on Highway 30 or

the Elwood Dr Exit off of it. Visibility in the area is low due to the exit being located on

the backside top of a hill. Because of this, there is an increased risk that drivers may

collide with stopped cars as they approach the exit at high speed.

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Figure 2 - Map of the primary exit to be examined

http://www.fpm.iastate.edu/maps/

This is a specific area where the problem occurs, but this type of situation can be found

at many other intersections and in many other towns. The problem that the team has

been presented with is the development of an automated system that can inform people

of these unusual traffic conditions before it is too late. The Ames location is used as an

example, but the team’s solution is adaptable to work at other similar intersections.

1.3.2 General Solution Approach

In order to address these problems, a system was designed to inform highway drivers of

unusually slow or stopped traffic ahead. The system consists of a group of light beam

sensors placed at the intersections of Highway 30 and Elwood Drive, I-35 Southbound

and Highway 30, and I-35 Northbound and Highway 30. The sensors connect to a

control system that receives a signal after each light beam is broken. The control

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system then determines the vehicle’s speed by detecting the time it takes the vehicle to

travel between the two sensors. Once a predetermined number of slow vehicles are

detected, the controller then communicates to a wireless communication device that

transmits a message to activate a sign warning drivers to slow down. After a

predetermined number of fast vehicles are detected, the controller then sends a signal

to the wireless communication device to deactivate the sign letting drivers know that

traffic ahead is flowing normally. Many technologies were considered in order to find

the system of sensors, controller and warning devices that were most cost effective at

alerting drivers of the increased danger.

Figure 3 - Layout of system

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1.4 Operating Environment

The final system is portable and must endure the shock and motion that are associated

with moving equipment. Since it operates outdoors the system needs to withstand the

outdoor temperature extremes and survive adverse weather conditions. Therefore,

moisture, impact, and wind resistance were also considered. Since the system is

designed to be near or on the shoulder of a road, it therefore needs to be safely

positioned and identified so that additional traffic problems will not be caused.

Figure 4 - West bound traffic approaching the Elwood Drive Exit 146

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Figure 5 - Exit 146, the primary location for system equipment

1.5 Intended Users and Uses

The following two sections include information about the intended uses and users for

the Highway Traffic Monitoring System.

1.5.1 Intended Users

This system is designed to be operated by trained event staff, Department of

Transportation staff or Highway Patrol Officers. To accomplish this, the system was

designed to be relatively easy to setup, use and take down. Staff members should be

familiar with how to operate and troubleshoot the system before they install or set the

system up.

The traffic monitoring system is going to be used by motorists, so the warning

messages and traffic information were selected accordingly.

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1.5.2 Intended Uses

This is a highway traffic monitoring system. Therefore, it is designed to be used on high

speed roads. It is not designed to function on low traffic, slow speed streets, because

there is not enough traffic to warrant a system in these areas. The system was

designed to monitor traffic on a single roadway that has as many as three feeding

roadways. The system is primarily designed to work for Iowa State University’s Elwood

Exit problem area, but the design is flexible so that it can be adapted for use at other

locations.

1.6 Assumptions and Limitations

The two following sections are lists of the assumptions and limitations that were

included in the planning.

1.6.1 Initial Assumptions List

A single roadway is monitored

No more than three feeding roadways are allowed

The maximum warning distance is 2 miles

Initially designed for Highway 30 onto Elwood Dr. (exit 146)

No rerouting of traffic is considered with design

DOT or ISU employees will install equipment

1.6.2 Initial Limitations List

Current DOT electronics signs may be used for testing (if applicable)

System is able to be removed and stored when it is not needed

System is able to be setup to work in different locations

System is able to withstand outdoor temperature and weather extremes

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System is able to distinguish between moving and stopped traffic

System is able to operate in a high traffic area

System is able to monitor two lanes of traffic simultaneously

System is able to operate for a minimum of 6 hours

System is able to be setup in no more than one man hour

1.7 Expected End Product and Other Deliverables

The end-product of this project was dependent upon available funding and design time

requirements. Possible end-products included:

Design proposal - A full design proposal report

This end-product will be completed. It should not require outside funding and is the

most possible to accomplish in the amount of time the team can allot for this design

project. A full design report will be provided including controller logic, communications

setup, system component location maps, parts and cost lists and assembly and

operations information. Schematic designs, computer system requirements, processor

specifications and hardware specifications will be included in the design. A

demonstration may be part of the overall design presentation.

Simulation - A working bench-top system

The simulation could go beyond the full design report and could include a controller that

communicates with one or more sensors and one or more warning devices. It is less

costly than a full prototype, but still requires significantly more funding than currently is

available. Outside funding will need to be found (potentially from the DOT).

Prototype - A fully working testable system

This would be the most difficult and costly to produce. Outside funding would need to

be found (potentially from the DOT). DOT equipment would also need to be loaned to

the team. In addition to the complete system design, the team would assemble and test

the equipment to make a functional traffic monitoring system. Considerable time will

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also need to be spent in obtaining funding, purchasing parts and working with

individuals from the Highway Patrol, DOT and ISU.

End-Product Selection

The most feasible end-product to develop was the design proposal. This was due to the

cost effectiveness and time constraints of the design. The 150 dollar budget allotted to

this project would have been exhausted on a single sensor. Much more funding would

have been needed to be obtained in order to implement a simulation or a prototype.

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Section 2 - Overall System Design and Layout

Section 2 contains details that cover the design and layout of the complete traffic

monitoring system. The final section compares the system that has been created by

this team with similar competing systems from other companies.

2.1 Approach Used and Progress Results

Included in this section are the design objectives, functional requirements, design

constraints, technical approaches, technical considerations, technical evaluation results,

testing approach considerations and recommendations regarding project continuation or

modification.

2.1.1 Design Objectives

Several criteria were identified as necessary objectives the system needed to meet.

These criteria are detailed below.

Low cost: The system should be affordable for ISU and the DOT. Keeping the price

as low as possible was the major consideration for the project. The more functional the

system the higher the overall cost would be. Considerations for cost included

installation fees, eminence costs, assembly costs, and the costs for the components

used. The cost of the overall system was a major driving factor behind the

technological considerations.

Near real time monitoring: The system must be able to monitor traffic in a real time

manner. The data analysis did not need to be done in real time, but needed to be done

as close to real time as possible. The faster the system can analyze data, the faster it

can warn motorists of impending problems. Real time monitoring directly affects power

consumption and communication requirements.

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Reliable operation: The system must be able to operate reliably for up to six hours at

a time. The system must be able to handle any errors presented to it and reliably output

dependable results. Reliable operation will depend mainly on power consumption and

effectiveness of the detection scheme that will be employed.

2.1.2 Functional RequirementThe requirements the system needed to meet to be considered a success are detailed

below.

Capture and analyze: The primary goal of the system was to detect the presence of a

vehicle and the speed of the vehicle. The analysis of the speed of the vehicle could be

done either by the sensor itself, or by a software system located elsewhere. The

system needed to be able to detect whether a car was present or not. All other

measurements fail if this primary objective is not met.

Communication control system: The system needed to be able to transmit the data

collected to a control system that would then either analyze the data, transmit the data

to a software system for analysis, or directly activate a system to notify motorists.

Notify motorists: The system needed to be able to warn motorist of impending traffic

problems. This can be achieved in a number of different implementations. The

notification could have been either a visual warning from a road side traffic sign, or an

auditory warning via a radio frequency, or a combination of the two. The main

consideration needed to be the amount of warning time for a driver to understand that

there was a problem ahead and be able to react to the problem.

2.1.3 Design Constraints

The following are constraints the system needed to be able to meet so as to ensure that

the system was going to operate effectively.

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Durable: The system must be able to operate under any weather circumstance found

in Iowa. This includes extreme high and low temperatures. This also includes high

winds. Falling snow should not disrupt operation, but significant accumulation was not

accounted for and can cause problems. This is because at this point traffic patterns will

already be irregularly slow. The system also needed to stand up to heavy rain. This

includes water-proof components and sensory systems that work in the rain. Hail is

another potential weather problem. The system should be rugged enough to handle

light hail without significant damage or sensing malfunction. In addition to these

extreme weather phenomena, the system must withstand high volumes of traffic without

breaking. The system’s ability to withstand the rigors of high volume traffic was a

serious constraint which was considered.

Cost Effective Design: Again the system needed to be affordable. With a limited

budget available a cost effective design was a major constraint of the system limiting

the potential functionality of the system.

Portability: The system needed to be easily moved, setup, and taken down before and

after each event. Portable options were difficult to find; however, many semi-portable

options have been identified. For a system to be completely portable many other

objectives needed to be met including low power consumption, wireless communication,

and easy on-site setup and removal. Many semi-portable options did not meet the

stringent requirements of a portable device but do meet a combination of the above

criteria. If the cost of a portable system is too great a non-portable or semi-portable

option may be necessary.

Expandability: The system needed to be easily and cheaply expanded to cover all of

the community. This is a part of the cost effective design. The system price directly

affects how easily the system can be expanded.

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Functionality: The system needed to be able to distinguish zero, stopped and moving

traffic. The system needed also to warn motorists of potential hazard areas. In order

to accomplish this, the system needed to communicate with all of its components.

2.2 System Layout The system layout section describes how and where the system is set up. This is

broken into two sections. The first is the component layout which details where the

system components are setup. The second section, location adaptability describes the

different locations where the system is designed to function.

2.2.1 Component Layout

This section details the layout of the system by stating where components are placed.

The placement of the sensors occurs at the location where traffic monitoring is desired.

The first light beam sensor is place just beyond the shoulder of the road so that it is not

obtrusive to the motorists. The light beam should be elevated to a height of 1.5’ to 2’

above the road surface. The reflector is placed directly across the road from light beam

sensor at the same height. The second light beam sensor is place 5.5’ down the road

from the first light beam sensor. Likewise the second light beam sensor is place on the

same side of the road just off the shoulder so that it is not obtrusive to motorists. It is

also elevated to a height of 1.5’ – 2’ above the road surface with its reflector directly

across the road form it at the same height.

The control system enclosure is pole mounted above the ground and wired up to the

light beam sensors. The communications system is connected to the control system

and mounted above it. Figure 6 shows the layout of the detection system.

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Figure 6 - Overhead detection system layout diagram

The display system is located off the shoulder of the road so that it is not obtrusive to

the motorists but can still warn them of the traffic conditions up ahead. The display

system should be placed anywhere from 2-5 miles down the road from the detection

system, limited by the range of the communications system.

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2.2.2 Location Adaptability

This section addresses the adaptability of the system. The system can be adapted for

several different types of ramps. This can easily be accomplished in part due to the

variable speed settings that the control system has. There are three operation modes

for fast, medium, and slow traffic (not including the diagnostic mode, which is not used

for traffic monitoring). Depending on the speed that the traffic normally flows on the

ramp a corresponding speed setting is selected on the PLC. The three figures below

show the medium, fast, and slow ramps respectively.

Figure 7 - Medium-speed ramp placement (Elwood Exit off HWY 30 West)

Notice that in figure 7 the ramp is exiting a highway onto a slower road with no quick

turns this makes it an ideal ramp for the medium speed setting.

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Figure 8 - High-speed ramp placement (HWY 30 West Exit off I-35 South)

Notice in figure 8 how the ramp exits an interstate onto a highway with no quick turns.

Since both roads have high speed traffic this makes it an excellent situation to use the

high speed setting on the PLC.

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Figure 9 - Low-speed ramp placement (HWY 30 West Exit off I-35 North)

Notice in figure 9 that the ramp clover leafs off the interstate to a highway. Since the

clover leaf requires traffic to slow down considerably this is perfect situation to use the

low speed setting on the PLC.

The variable speed settings are used to help make the system more adaptable to

various types of exits. This increases the portability and ease of use of the system.

The speed ranges are adjusted as follows.

Table 1 - Speed adjustment ranges

Setting Slow car if under Fast car if overLow 10 mph 25 mphMed 15 mph 30 mphHigh 25 mph 45 mph

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2.3 System Flow

In this section the flow of the entire system is outlined. A detailed explanation is given

on how the sensors detect traffic, how the control system interprets the information

gathered by the sensors, and then how the control system communicates with the

display system in order to warn on coming motorists about the traffic conditions up

ahead.

The light sensors are used to detect the presence of traffic on the exit ramp. When a

car breaks a beam a signal is sent. In order to get a reading of the vehicle speed two

light beam sensors are used. This information is sent to the control system.

The control system is used to interpret the data that is read from the sensors. The basic

formula used to determine the speed of a vehicle is the distance between the two

sensors divided by the time between the breaking of the first beam and the second

beam. There are some traffic conditions that do not allow for the speed of the vehicles

to be determined so easily. Many of these complicated cases occur with monitoring

two-lanes of traffic with one set of light beams. All traffic conditions including these

more complicated scenarios are outlined in the table included as Appendix A.2. The

control system was tested under simulations of all of these traffic conditions and

performs well as a monitoring solution for both single and dual lane traffic.

In order to handle these various traffic conditions flow charts were created to clarify how

the PLC code should behave and operate. To obtain a complete understanding of how

the system functions please see all of the flow charts which are included in Appendix

A.1. The flow charts describe the flow of the program. The PLC ladder code is also

located in Appendix A.3. This code is thoroughly commented so that its complete flow

can also be understood.

The basic operation of the system was designed to be relatively simple. Once the PLC

has detected 2 slow cars, not necessarily consecutive, then the on coming motorists

20

need to be alerted of the slow moving traffic conditions. The control system then

communicates with a message board that can be positioned 2-5 miles away to warn

motorists that the traffic is going slow. Once three fast cars are detected by the PLC the

message will be cleared so that motorists will know that traffic conditions have

improved.

The PLC will be connected to a radio transmitter via contact closure. This means that

the PLC only needs to send a high voltage signal whenever slow traffic is encountered.

Once the transmitter sees this high voltage, it will transmit a signal to a receiver (the

receiver is connected to the display system), which can be located 2-5 miles away.

The display system has a radio receiver connected to it that will listen for the

transmitter. The receiver will use contact closure to turn on the flashing lights once a

warning signal has been received from the transmitter. A simple metal sign displaying

“Slow traffic ahead when flashing” will be used in tandem with the flashing lights.

This system can be adapted for various kinds of exits. Making it portable to other

locations where it is deemed that a traffic monitor and warning system is needed.

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Section 3 - Component Design

This section contains the summaries of the designs for each of the four system

components; sensing, control, communication, and display. The full technology

selections are included as appendices to provide a complete understanding of the

component selection process. These complete sections are very lengthy, but they

include a large amount of data and should be consulted if more information on the

technology selection is desired.

3.1 Sensor System

This section is a summary of the complete design of the sensor system. More

information is included in Appendix B.

3.1.1 Sensor System Overview

Sensor technology research received the largest amount of attention during the starting

phases of the project. This was expected, since the starting point of the system process

is sensing the vehicles. Spending more time on the proper selection of sensing

technology was also important because of the significant impact that it would have on

later determining control and communications technology requirements.

For this system several sensing requirements had to be met. To begin with, the sensor

had to be able to detect the presence and speed of a vehicle. Next, the team analyzed

each sensor’s reliability, accuracy, durability, and cost. The cost of each item was

broken up into two categories; initial cost, and operating cost. Initial costs covers the

expenses associated with the purchase of the sensor, assembly costs, and installation

of the sensor in the field. Operating cost includes the expenses associated with

setup/take down, regular maintenance, and any other costs of operating the unit. A

thorough description of all of these evaluation criteria can be found in Appendix B.1.1.

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3.1.2 Sensor System Evaluation

Each sensor was extensively compared on the aforementioned traits. The following

table provides a quick glance at some of the technologies evaluated and their strengths

and weaknesses. See Appendix B.1.2 for the complete detailed evaluations.

Table 2 - Sensor system evaluation overview

Technology Description Advantages Disadvantages

Radar GunRadar gun detects speed of car Gives actual speed Minimum speed threshold

Video CameraHuman or computer detects car via camera Versatility 

Human or computer required to operate

Strain Gauges  Detects weight of car Low price Lack of durability

Wire loop  Inductive loop detects car Proven technologyExpensive installation, permanent

Road Tubes Pressure difference detects tires Proven technology

Prone to failure, constant replacement

Tape Switches Switch detects tires Portable Expensive, low durability

Light BeamBreak in light beam detects car

Cheap, durable, portable, simple Weather problems

3.1.3 Sensor System Selection

From the analysis performed, a final technology was selected. The following table

shows the results of each sensor’s evaluation.

Table 3 - Evaluation of sensor technologies based on identified criteria

The light beam scored the highest overall and will therefore be the technology that will

be used for the sensor system. This is primarily due to portability, initial cost and ease

of implementation.

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An IFM Efector infrared reflective beam sensor has been selected for this system. IFM

Efector manufactures rugged, accurate and sensitive light beam units. They have been

proven reliable by a team member who has used them in industry. The exact unit and

accessories are listed in the complete parts list which is included as Appendix A.4. The

total cost is under $200. This includes the sensors, reflectors, and cables.

Figure 10 - Selected infrared reflective light beam sensor

http://www.ifmefector.com

A system that utilizes a reflector instead of a pass-through beam was selected to

eliminate the need to run cables across the roadway. The selected sensor has a range

of 13.5 meters which is long enough to cross a two-lane road if so desired. They also

operate off of 24 volts which will be supplied from the control system’s batteries. The

complete datasheets for this unit are included in Appendix B.2.

If a more permanent solution is desired, an in-ground wire loop system similar to one

used at a stoplight is recommended. This system was not selected as the primary

sensor technology because it does not meet the portability requirement and has a much

higher initial cost due to required pavement work. This initial cost could be offset by

quicker setup times and higher durability.

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3.2 Control System

This section is a summary of the complete design of the control system. More

information is included in Appendix C.

3.2.1 Control System Overview

The control system has to be able to handle all of the necessary inputs that will be

presented to it from the sensor system. In addition, the control system must be able to

connect with and send data over the wireless communication system. The control

system is responsible for all the necessary speed calculations, processing, and

communication processing for the system.

Initially the group had planned on implementing a computer using software to operate

the control system. The main advantages to this would be the ability to communicate

using wider variety of protocols and the familiarity the team had with existing computer

systems. This option was later deemed to expensive in both actual cost and operating

power and will not be examined here. If interested, please refer to Appendix C for a

detailed analysis of this option.

After finding that the complicated communications options would not be needed, the

team changed focus programmable logic controllers (PLC’s). They are simple, rugged

devices that can be programmed to perform all that is required of the control system.

When connected with the correct contact-closure wireless communication system they

are also very easy to implement.

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3.2.2 Control System Evaluation

These PLC control systems were each evaluated on the following criteria: capability,

durability, ease of implementation, initial cost, power consumption (operating cost) and

programming software package. See Appendix C for the detailed evaluation.

Table 4 - PLC-based control system evaluation overview

Technology Description Advantages Disadvantages

Allen-Bradley PLC MicroLogix 1000

Group member has programming experience

Operating temp, expensive software

Mitsubishi PLC Alpha Operating temp No programming experience

GE Fanuc PLC VersaMax Nano  Price

Operating temp, no programming experience

3.2.3 Control System Selection

Overall the PLC’s that were examined all shared roughly the same features that will be

required for this project.

Table 5 - Evaluation of PLC control technology based on identified criteria

PLC Capability Ease of ImpInitial Cost Op Cost Durability Ease of use Total

AB 25 20 5 5 10 5 70Mitsubishi 25 0 10 10 25 5 75GE Fanuc 25 0 15 5 5 5 55

In general, the best choice for a PLC would be the Mitsubishi Alpha Series. This is

primarily because it is the most durable in cold weather.

The Allen-Bradley MicroLogix 1000 was rated as a close second option. Its largest

weaknesses are a higher minimum operating temperature and its expensive

programming software. However, this expensive software is currently owned by the

university which made this system the best initial cost option for this design project.

26

With these additional 10 points, the MicroLogix becomes the best overall option for this

team. In addition, a team member has considerable knowledge in programming these

PLC’s and a control system lab has two units that are available for programming and

testing at no cost.

Figure 11 - Allen Bradley MicroLogix 1000 PLCwww.ab.com

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3.3 Communication System

In this section the communication system is summarized so the reader will get an

overview of the technology selected and why it was selected. For a more detailed

analysis of all the communication systems researched and the process by which these

systems were rated please look in Appendix D – Communication System.

3.3.1 Communication System Overview

In order for the display system to accurately warn the on coming motorists a

communications system is needed to relay the warning from the PLC to the display

system. The communication must occur wirelessly and also must have a range of at

least 2 miles in order to give the motorist ample warning time. It must also have a

simple protocol and easily interface with a PLC.

There were two major technologies considered to handle this task. They were radio

communications and cellular communications. The cellular communications would have

required the creation of a transmission protocol to communicate with the cellular display

system. The radio communications would not require a protocol. For this reason the

radio communications technology was selected over the cellular communications.

Radio communications was researched further in order to find the one that would best fit

the requirements of the system.

3.3.2 Communication System Evaluation

There were two similar radio communications systems that were identified; the Encom

Wireless model #7314 and the Remote Control Technology model #01210. Both

allowed for contact closure inputs on the transmitter and contact closure output on the

receiver. This would make integration with the control system and the display system

much more efficient and simple. Each system was evaluated and given a score as

shown in the table below.

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Table 6 - Communication system evaluation overview

Technology Description Advantages Disadvantages Encom Wireless  Model #7314 Price, Radio range  ImplementationRemote Control Tech  Model #01210  Implementation Price, radio range 

3.3.3 Communication System Selection

The communications system that was deemed as best fit for the system was the Encom

Wireless model #7314. The full evaluation specifications can be seen in Appendix D.1.

Table 7 - Evaluation of communication technology based on identified criteria

This was due in large part because it had a long communication range and cost less

than the system produced by Remote Control Technologies. The Encom Wireless

system costs $2550.

Figure 12 - Encom wireless communication systemwww.encomwireless.com

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3.4 Display System

In this section the display system is summarized so the reader will get an overview of

the technology selected and why it was selected. For a more detailed analysis of all the

display systems researched and the process by which these systems were rated please

look in Appendix E - Display System.

3.4.1 Display System Overview

The display system needed to be able to communicate to motorists a warning of the

slow traffic conditions ahead. There were three different technologies that were

considered while trying to select which one would be best fit as a display system.

These three technologies needed to be evaluated in order to identify the one that would

be best fit for the system. These three technologies were an FM radio broadcast,

message boards, and flashing lights with a sign.

3.4.2 Display System Evaluation

FM Radio Broadcast

Pros: The FM radio broadcast had the advantage that it could convey the message to

each individual car and not just one specific location like that of the message

board or flashing lights.

Cons: It was very expensive. A price quote of $23,000 was attained from Highway

Information Systems. This was very expensive, especially when considering an

additional sign would be needed to tell motorists to tune into a radio station for

a traffic report.

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Portable Message Board

Pros: The portable message board has the advantage of being dynamic plus it can

convey information to the motorists without requiring them to tune to any radio

station. The messages it displays can also be modified depending on the

various traffic conditions.

Cons: Communications between the PLC and the message board would be complex.

The types of portable message boards currently owned by the IDOT are from

different providers and each provider uses a different communications protocol

to operate the sign at this point in time. The estimated cost of one of these

signs is around $10,000 to purchase used.

Flashing Lights with Road Sign

Pros: The flashing lights with a road sign is the easiest to implement of the three

options. This is due to the fact that contact closure can be used by a radio

receiver to turn on the signs. This simplifies the communications and the

control system interface with the communications. It is also the least expensive

option.

Cons: Only one message can be displayed.

3.4.3 Display System Selection

From the analysis performed in the previous section, a final technology was selected.

The following table shows the results of each display system’s evaluation. The full

display system evaluation results can be seen in Appendix E.1.

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Table 8 - Evaluation of display technology based on identified criteria

The radio broadcast system scored the lowest, overall. This is because the system

should only be used in conjunction with one of the other two options. For a more

dynamic system, a warning sign with flashing lights and the radio could be used

together to effectively alert traffic, for a price.

The sign and lights system was selected because of its simple implementation and

lower cost. If the communication system selected in section 3.3 is used then the 12”

yellow traffic light from OkSolar (part # 170709) could be used which costs $185.24. A

road sign saying “slow traffic ahead when flashing” is also required (approx. $100).

Instead of adding additional testing and construction costs to create this system, an

already manufactured system has been identified. The system implements both the

needed contact-closure wireless communication system and the flashing light warning

sign. It is further discussed in the flowing section.

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3.5 Combined Communication and Display Option

There is a system that is produced by OkSolar that combines the communication

system and the display system into one. This system was identified separately from the

other radio communication systems because it includes the display system with it.

Below is a picture of the solar powered standard flashing yellow LED sign and mount

with wireless receiver.

Figure 13 - OkSolar warning sign with flashing lightwww.oksolar.com

Figure 14 - OkSolar communication system transmitterwww.oksolar.com

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Above is a picture of the remote transmitter that communicates with a one way

monitoring 900 MHZ receiver using contact closure. The system can communicate over

the range of 2-5 miles. This would be the ideal system to use because it is simple, self-

powered, and incorporates the communications with the message system in one

already tested system. This option will also reduce testing and construction time.

The communications unit costs $2495 and the display/sign, which includes a solar panel

for power costs $1725. The only adjustment required would be to purchase a sign

reading “slow traffic ahead when flashing” for approximately $100. The complete parts

list in Appendix A.4 includes this system for the communication and display section.

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Section 4 - System Construction, Setup, Operation, and Comparison

This section contains information, instructions, and suggestions for the construction,

setup, and operation of the highway traffic monitoring system.

4.1 System Construction

In order to build a prototype system, all of the items on the complete parts list (Appendix

A.4) would need to be purchased. The main enclosure is where the most complicated

assembly will take place. This is where the sensors, controller, and communication

system will all be connected and operated from. The inside of the enclosure should

contain the items shown in the image below.

Figure 15 - Inside view of main enclosure with dimensions

35

The drawing above is to scale, so it is easy to see that the batteries will take up the

most room in inside the enclosure. The cabinet is also 10 inches deep in order to fit

these batteries. The batteries are specialized batteries which are sealed in order to

prevent gas venting which could cause an explosion. The thermostatically controlled

heater is included in order to regulate the system temperature for extreme winter

conditions. The parts list also includes 1/2 inch Styrofoam insulation for the cabinet to

help reduce battery drain from the heater and to help provide consistent operating

temperature.

Below is a picture of the exterior of the enclosure. It shows the control switches and the

indicator lights for the system’s operator. Notice that these items are located in a row

slightly above center. This is done to provide space for them inside the cabinet, above

the batteries, and below the PLC and heater.

Figure 16 - Front view of main enclosure with descriptions

36

The basic wiring of the system is relatively straight-forward. All enclosure devices were

chosen to run off 24 volt DC power which is provided by the two 12 volt batteries when

they are wired in series. The main system on/off switch is connected to the 24 volt

source and used to power all system components. The sources of all switches are also

connected to this switch in order to provide a 24 volt signal to the PLC when they are

closed. The actual wiring is further described in the following wire landing table.

Table 9 - Wire landing table

The communication transmitter enclosure will be mounted above the main control

enclosure. It will need to be wired to receive power and the PLC warning output. This

control output will energize its input detection contact and trigger it to send an energize

signal to the warning sign.

The sensors will also need to be connected to the main enclosure by means of their

included cables. They will receive power, and a 24 volt source which will be switched

by the sensor to provide a signal to the PLC and indicator lights.

To make wiring easier, it is recommended that terminal strips and wire numbers are

used. This will help organize the wiring and provide a clean way to complete multiple

37

connections to one source. For example, the main power button will have many

connections. To improve setup time, quick disconnect plugs should also be used to

hook-up the sensors and communication system to the main enclosure.

This assembly and wiring will complete the basic construction of the system. The

display system chosen is a stand-alone unit with its own power source and receiver.

This system will most likely also require some assembly, but instructions for that will be

provided by the manufacturer.

4.2 System Setup

Once the system has been constructed, it will need to be setup at the desired location.

As long as the system layout specifications (Section 2.2) are met, the system can be

setup as desired by the client. Because methods will depend on location and cost will

very greatly, this area has been left open for modification.

The simplest method would be to mount the system on wood or steel posts. This is a

cheap, permanent to semi-permanent solution. The semi-permanent solution would

involve leaving the posts, but allowing the components to be removed and mounted

quickly for individual events. A fully-portable solution would be mounting everything on

stands, carts or trailers. This would be considerably more expensive but would also

allow the system to be positioned at different locations with ease.

It is also important to note that the system’s batteries currently require charging after

each event for which they are used. This is done to reduced cost and increase

portability. If a permanent mounting solution is desired, the system could be connected

to a solar charging system or to AC power using a converter.

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4.3 System Operation

The system has been designed to be very simple and straight-forward to operate. The

following are the basic operating instructions.

Prepare the system – Charge the system before an event using the 12 volt battery

charger included on the parts list (or a similar automotive battery charger). It is

suggested that the batteries be disconnected from the system and charged individually

to limit the possibility of damaging any components.

Prepare the site – If using a simple post mounting system, drive in the posts to support

the two sensors, the control and communication system, and the display system. If

using a portable solution, properly position the equipment. See Section 2.2 for detailed

system layout specifications including mounting distances and equipment locations.

Energize – Once the system is properly mounted at the desired location turn the

system on using the On/Off push button. Check that the sensors are aligned properly

so that both of the beam indicator lights are off (they will light when they are not getting

a reflected signal).

Test – The system has been designed with a diagnostic setting. See Appendix F.1 to

see the complete diagnostic testing procedure. Upon diagnostic completion, reset the

system with the Reset push button.

Monitor Traffic – Now the system is ready to monitor traffic. Check the system

occasionally for proper operation. Use the system reset switch if the system warning

needs to be manually disabled.

Disable and Remove – When the event is over, press the Reset push button to clear

the system and ensure that the warning display is deactivated. Power-down the

system using the On/Off button. Remove the system and store until next use.

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4.4 Complete System Comparison

This section contains a comparison between the proposed system and prefabricated all-

in-one systems from two companies in the traffic monitoring industry.

4.4.1 Complete System Overview

The two systems that will be compared to the proposed system are manufactured by

Nu-Metrics and International Road Dynamics (IRD). To evaluate these systems,

important criteria were identified and are included in Appendix F.2.1. Included as

Appendix F.2.2, is a complete description of the each system. The basic differences

are summarized in the next two paragraphs.

The Nu-Metrics system uses in-road magnetic sensors that need to be drilled into the

road. These sensors collect information about the vehicles passing over them and are

usually used to record traffic information such as vehicle speeds and lengths for later

analysis. The system would need to be modified to control a sign with flashing lights,

but it was believed that this could be done using an existing wireless communication

system. Because of the cost related to modifying this system to perform the desired

warning task, further design was halted until funding could be provided to continue the

company’s development.

The IRD system would be the opposite of the Nu-Metrics system in terms of portability.

It is completely trailer mounted to be fully-portable and quickly setup. This increases its

initial cost, but gives a great advantage in the long term with lower operating cost. It

utilizes a non-intrusive microwave sensor to detect speed and uses wireless

communication to operate a sign with flashing lights similar to that used by the system

developed by this team. This system can also be improved upon with the addition of

web-based monitoring, paging and the control of electronic message boards.

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4.4.2 Complete System Evaluation and Recommendation

All three systems vary greatly from one another in capability, durability, portability, ease

of use and overall cost. For this overall system selection, each system will be evaluated

and all three options will be given. They will be classified by their abilities and

respective cost. This way, depending on the available funding and specific situation

requirements, any one of the systems may be selected to best meet the given

constraints.

Team Designed SystemThe highway traffic monitoring system that was designed by this team is by far the

cheapest solution, costing less than $6,000 per system for parts (see Appendix A.4 for

complete parts list). Depending on the number of systems created, additional cost will

need to be included for the design, construction and testing. If multiple systems are

produced, a simple post-mounted system should be able to be created for under

$10,000. For its minimal cost, it should be reliable, portable and effective. It is also

adaptable for different types of exit ramps and their respective speeds. Unfortunately,

the cheaper post-mounting system will also require the most amount of time to setup.

To improve portability additional cost would be associated with the construction of

portable stands or even trailers which would make the cost of this system more

comparable to that of the IRD system.

If initial system cost is the driving factor for the selection process, this is the best option.

It was specifically design to be the low-cost option. For a much lower cost, it provides

most of the functionality of the more expensive solutions. Besides setup time, its

primary set backs are the fact that is not thoroughly tested and that it does not include

any technical support which the other companies can offer with their products.

Nu-Metrics SystemThe Nu-Metrics system is currently difficult to evaluate because its full abilities and

rough cost are not known. It is a durable, permanent system that could also record

41

traffic flow data. If this functionality was desired, additional research could be

conducted with Nu-Metrics to develop this system. Because this would be a permanent

solution, it would make it the easiest to operate for an event because it would not need

much setup time.

International Road DynamicsThe IRD system appears to be the “Cadillac” system. It is the most capable and it has

already been tested and proven. Its trailer based construction also makes it completely

portable with easy setup. This is a great advantage because this system could now be

easily used by other entities than just Iowa State University. This would allow the high

cost to be split among multiple users. With its non-intrusive sensing, completely

wireless operation and simple portability, this system is very impressive. If the roughly

$38,000 could be obtained to purchase this system, it would most certainly provide the

best overall performance.

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Section 5 - Closure Material

Contained within this section are the project team information and the conclusion.

5.1 Project Team Information

This section contains information about the client, faculty advisors, team members, and

the project website.

5.1.1 Client

Iowa State University

5.1.2 Faculty Advisors

Professor John Lamont

324 Town Engineering, Iowa State UniversityAmes, Iowa 50011515.294.3600 office515.294.6760 faxjwlamont@iastate.edu

Professor Ralph Patterson III

326 Town Engineering, Iowa State UniversityAmes, Iowa 50011515.294.2428 office515.294.6760 faxrepiii@iastate.edu

Duane E. Smith, P.E.

Associate Director for Outreach, ISU Research Park2901 S. Loop Drive, Suite 3100Ames, Iowa 50010-8632515.294.8103 office515.294.0467 faxdesmith@iastate.edu

43

5.1.3 Student Team Information

Ben Armfield

4701 Steinbeck St #4Ames, IA 50014515.451.1207 cellbenjarm@iastate.edu

Joel Cardo

311 Ash AveAmes, IA 50014515.450.3895 celljcardo@iastate.edu

Wendell Cotton

325 Ash AveAmes, IA 50014515.708.2189 cellwcotton@iastate.edu

Brent Duppong

PO Box 1252Ames, IA 50014-1252319.310.3053 cellbduppong@iastate.edu

5.1.4 Project Website

http://seniord.ee.iastate.edu/may0506/

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5.2 Closing Summary

This document has covered the design process that the team proposes for the

development of this project. The team worked toward creating an appropriate and

affordable design for minimizing traffic risks associated with the Iowa State University

campus and facilities. Because traffic accidents often occur when a major athletic event

or concert is held at Iowa State University, it was important that a portable system be

developed to detect slow moving or stalled traffic and notify motorists of the congested

traffic conditions ahead. The proposed Highway Traffic Monitoring System helps to

alleviate congestion, prevent accidents and increase the overall traffic flow to and from

these events.

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5.3 References

Iowa Transportation Center and Iowa State University, “Cyclone Stadium Traffic Study.”

Iowa State University; September 1993.

46

Appendix A - Overall System Layout and Design

This set of appendices includes all additional information related to the overall system layout and design.

A.1 Flow Charts

Main Flow

Figure 17 - High level flow diagram of the control logic

System Reset

Figure 18 - Flow diagram for system reset

47

Check for Traffic

Figure 19 - Flow diagram of traffic detection

48

Determine Speed

Figure 20 - Flow diagram for determining traffic speed

49

Display Message

Figure 21 - Flow diagram for displaying a message

50

Blocked Sensor

Figure 22 - Flow diagram for detecting a blocked sensor

51

A.2 Traffic Condition List

Table 10 - Possible traffic system condition list

52

A.3 PLC Ladder Code

53

54

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Table 11 - Address table showing integer time values

This table is included because it is the only address table that has values specifically

assigned in it. The zero value cells can be ignored as they are not used. The numbers

entered in rows N7:10 to N7:40 are used to store time values for the four different speed

settings; slow, medium, fast, and diagnostic. Notice that the diagnostic speed settings

are much slower at over 400 (4 seconds) for a slow car and under 200 (2 seconds) for a

fast car. The row N7:0 is used to store the current speed setting (here it is shown with

the default medium speed setting values). These numbers could easily be altered after

actual road testing is completed in order to tune the system.

See the ladder logic comments to see how the addresses are specifically copied and

written.

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A.4 Complete Parts List for Highway Exit Monitoring System

Table 12 - Complete parts list

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Appendix B - Sensor System

This set of appendices includes all additional information related to the sensor system.

B.1 Sensor Technology Evaluation

This section contains appendices which provide additional information about the sensor technology evaluation.

B.1.1 Sensor Technology Criteria Identification

This section will detail the criteria used to narrow the sensor selection down to the final

optimal solution. The following criteria were used to determine the selection of the

sensors.

Capability: This factor takes into account the sensor’s ability to meet the design

objectives, functional requirements and design constraints of the project. The accuracy,

reliability, safety and expandability of the system are key components.

Ease of implementation: Ease of implementation is the next most important criteria.

Due to the limited time constraints of this project, the group favored as many “off the

shelf” parts as possible. The level of difficulty involved with designing the system using

the given sensor technology was also analyzed.

Initial cost: Initial costs include the price of components for the unit, assembly, and

installation costs.

Operating / maintenance cost: This factor deals with setup of systems that have to be

installed and removed before and after each event. Also, this factor deals with the

maintenance costs of each unit. This includes storage and basic maintenance to the

unit.

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Durability: Durability is another important factor in choosing a sensor. The system

needed to be able to withstand all of the natural elements and in addition survive

thousands of vehicles driving over or past it.

Ease of use: Ease of use is an important factor when considering the operation of the

sensors. It is undesirable to need to train people how to use a difficult sensor system.

It is also best to have the system be easy to setup due to time constraints before and

after an event. Therefore, even if systems are equal based on a sum of the initial and

operating costs; this factor accounts for the advantage of having an easy to use system.

These criteria are weighted as follows:

Capability 35 PointsEase of implementation 20 PointsInitial cost 15 PointsOperating / maintenance cost 15 PointsDurability 10 PointsEase of use 05 Points_______________________________________Total 100 Points

The weighting was decided based on the overall design objectives, functional

requirements and design constraints. Considerable time was taken to develop a fair

and accurate grading system.

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B.1.2 Sensor Technology Identification and Research

Several technologies were researched in order to find the most cost effective and

reliable sensing devices. For the identification part of this section, the operation of

these systems, and some of each system’s advantages and disadvantages were

provided. The research was documented by listing how each technology performed

based on the criteria that were previously identified. A final, overall ranking of each

technology is supplied.

Radar Gun / Motion Detector

Operation: The radar gun/motion detector combination was the first idea the group

evaluated. This sensor system would consist of a radar gun with an output

device and a motion detector. The motion detector would be connected to

the radar gun, which would then be connected to a transmitter that would

send the radar gun’s output to a server. The motion detector would detect a

vehicles presence and fire the radar gun at a predetermined location to

detect the vehicle’s speed. The radar gun would then output the speed to

the transmitter and send the information to the server to be processed.

Figure 23 - Example of a radar gun with serial output

http://www.opticsplanet.net

60

Pros: The radar gun/motion detector system can detect the speed of the moving

vehicle with one sensor location. In addition, this is a non-intrusive form of

vehicle monitoring which would eliminate most of the wear problems

associated with road mounted systems.

Cons: This system is by far the most difficult to make. There are many potential

problems that may arise from the implementation of this system. Among

these is the minimum speed sensing range of radar guns. Radar guns can

not detect cars going below a certain threshold depending on the gun.

Research has found that this can be anywhere from 5 to 20 mph. This

could be a serious problem if the motion detector is detecting motion, such

as a car inching along, and the radar gun is not able to determine a speed.

In addition, radar jammers would create havoc on the system. Other

problem areas are interference from other sources such as police vehicles,

ambulances, and other vehicles operating on the same frequency as the

radar gun. Other issues that would have to be overcome include making

the motion detector control the radar gun, decoding the output of the radar

gun, and transmitting that information to the server. The price of the system

is also fairly high with each radar gun costing over $900 dollars and each

motion detector costing approximately $100. The output from the gun

would also have to be converted using additional components in order to

transfer it to a computer.

Capability (10/35): The minimum speed requirement of the radar gun will severely

deter its ability to perform the most basic required function, detecting a slow moving

vehicle.

Ease of implementation (0/20): The radar gun is the most difficult to implement as a

technology. It will require an extensive control design along with a complex controller to

properly decode the information generated by the radar gun.

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Initial cost (7/15): The price of the system is fairly high with each radar gun / motion

detector set costing over $1000. Controllers and data converters will also need to be

purchased. In order to be portable, the system could be trailer mounted to be easily

setup in the field. However, this would greatly increase the cost of the units.

Operating / maintenance cost (10/15): With the unit trailer mounted, the operating

cost would be relatively low. The equipment would still need to be maintained and

everything would need to be positioned and adjusted properly for each setup.

Durability (6/10): The durability of this system should be pretty high as it will not be in

direct contact with any traffic and will only have to survive transportation to and from the

site. Weather elements may prove to be more troublesome to the system as rain as

snow could easily affect the motion detector’s accuracy.

Ease of use (3/5): The radar gun system may be fairly easy to use assuming that it is

trailer mounted. It would simply need to be setup and positioned correctly.

Total score: 36/100

Video Cameras

Operation: Video cameras would be mounted on light poles that are already present at

the Elwood Exit. There are two different ways in which the cameras may be

used. First, they would be connected wirelessly to a remote viewing station

where an operator would monitor traffic and control the warning system to

appropriately alert the drivers. The second option is to have the video feed

be monitored by a computer system. The system would be calibrated to

detect vehicles and calculate their speed. Once the average speed of

vehicles on the ramp is found, the appropriate warning system would be

triggered automatically.

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Figure 24 - Weather resistant camera mounting option

http://www.ses-sikring.dk

Pros: The human system has the most versatility because the operator is able to

monitor the dynamic system more effectively. The computer controlled

camera system can detect the speed of the moving vehicle with one sensor

location. The system would also be able to detect if a car is present or not.

The video cameras are a non-intrusive form of vehicle monitoring which

would eliminate most of the wear problems associated with road mounted

systems.

Cons: The human operated system does not necessarily fall into the scope of the

design requirements because it is not automated. In addition this system

will become extremely expensive over the long run due to the costs of

having an operator run it. Another potential problem would be the wireless

transmission of the amount of data that a camera creates. The computer-

based image processing is also an unfamiliar technology which would be

difficult to implement.

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Only the automated video monitoring system is going to be evaluated. Having a person

watching cameras does not meet the design objectives and is not an effective system.

However, to reduce cost and be more effective, a person could simply monitor traffic at

the location and activate the sign manually.

Capability (20/35): Motion capture technology may have problems discerning the

speed of vehicles in poor light and weather conditions. The technology should be able

to detect both the presence of a vehicle and its speed, which is an advantage over

some of the technologies.

Ease of implementation (2/20): The video camera system should be fairly easy to

setup because it employs many off the shelf parts. Unfortunately, the motion capture

technology requires large amounts of programming knowledge that is unfamiliar to the

project team. This is a new technology that would be difficult to implement.

Initial cost (0/15): The cameras can be purchased for approximately $250 and the

base station required for the cameras cost close to $100. Installation may be expensive

with extensive wiring work. Continuous high-flow wireless transfer would be very

expensive. Computerized image analysis system is also most likely very expensive.

For portability it would be assumed that the cameras would also need to be mounted on

trailers.

Operating / maintenance cost (8/15): If the system is trailer mounted it will not cost a

lot to operate, but there will still be maintenance cost similar to the radar system.

Durability (4/10): The cameras are quite durable but may have some problems

focusing during high wind. The image processing software would most likely have

trouble in heavy rain, snow or fog.

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Ease of use (2/5): The ease of use of this system is going to be fairly low because the

cameras will also need to be cleaned and adjusted often. Positioning them properly and

calibrating the detection system may also be difficult.

Total score: 36/100

Strain Gauges

Operation: The basic operation of this system would require a simple microcontroller

and a strain gauge. The idea behind this system would be to mount a strain

gauge underneath the pavement to measure the flex in the pavement that a

car creates when it drives over that section. The speed of a vehicle would

then be calculated based on the time that a car is on the sensor. After a set

amount of speeds have been collected, the controller would then send a

signal to the proper sign that displays a warning message. The sign would

remain active until the server receives a signal from the strain gauge system

that says a car has been on the strain gauge for a very short amount of time

(indicating that a car is moving quite fast) the server would then clear the

proper sign. This basic idea will be the same idea behind the wire loop,

road tube, tape switch and light sensor systems.

Figure 25 - Example of a concrete strain gauge

http://www.mrr.dot.state.mn.us/research/MnROAD_Project/

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Pros: This system has the benefit of being a very cheap system employing a very

novel way to detect the speed of traffic. Event setup would be simple

because the units would only need to be connected to the system. The

sensor pictured above costs less than $100.

Cons: This system would require a great deal of concrete work to install. Weather

would also create a problem with this system. Freezing of the concrete

could generate a false signal. This would be a major problem seeing how

the system is to be implemented in Iowa. The system may not be sensitive

enough to detect high-speed vehicles.

Capability (20/35): The strain gauge is an unproven technology for this purpose, but

the concept behind the technology is strong. In most situations this system should

perform properly but extreme heating and cooling of concrete could potentially corrupt

the reliability of the system.

Ease of implementation (4/20): This is a difficult technology to implement requiring

extensive decoding of information. The detection circuitry required of this system may

prove problematic and will add another element to the system. The accuracy of the

components would be difficult to know without significant and expensive testing.

Initial cost (3/15): This system will be extremely cheap to implement with each strain

gauge costing under $100. However, this system will require extensive assembly and

installation road work which will drive its initial price extremely high relative to how

simple the technology is. Initial testing of the strain gauges would also be expensive

because they would need to be embedded in concrete and driven over by normal traffic.

Operating / maintenance cost (12/15): This system will require little maintenance in

ideal weather conditions. However, replacement of damaged units could become

expensive and is expected, due to the fact that they are an on-road solution.

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Durability (7/10): The durability of this system is a little unknown. Since it is an

unproven technology no one knows if the delicate sensor will be able to withstand the

large amount of traffic driving over the top of it. Because it is mounted in the road, this

system can be plowed over in the winter and should be generally unaffected by

precipitation.

Ease of use (5/5): This system would most likely be a non-portable to semi-portable

solution. The operator should only have to connect the sensors to the system for each

event. Because the sensors do not need to be positioned for each event, this

technology receives the highest score.

Total score: 51/100

Wire Loops

Operation: The operation of this system uses the same logic as the strain gauge.

However, instead of using a strain gauge to detect the presence of a vehicle

a wire loop similar to the wire loop used at a stoplight would be used. A

magnetic field is created by the loop. The sensor measures the disturbance

in this field when a vehicle passes over it. A pair of loops would be installed

at a set distance apart from each other. The time it takes a vehicle to pass

both sensors would in turn be used to calculate speed. Two different types

of wire loop systems are going to be evaluated. First, there are in-road

loops which are cut into the pavement. The second option is to use

temporary loops which are adhered to the road surface. Both loops are

cheap because they are simple coils of wire. However, the in-road loops

initially cost more to install because of the concrete work and are obviously

not mobile. On the other hand, the temporary loops are portable and will be

cheaper at first, but they may become more expensive in the long run

because they will be damaged much faster than in-ground loops.

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Figure 26 - Example of an in-ground wire loops

http://products.irdinc.com

Figure 27 - Example of a temporary on-road loop

http://products.irdinc.com

Pros: An advantage of this system is that it is based off commonly used

technology. This would benefit the DOT because they already have

experience installing these systems. In addition this would be a relatively

cheap system that uses pre-existing technology. This system should be

able to work in most weather conditions and the in-road systems should not

pose any snow plowing problems similar to pre-existing systems.

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Cons: The major downfall of the in-road loop system would be all of the expensive

concrete work required to install the system. The system would no longer

be portable. The portable loops could become very expensive in the long

term. These mobile loops may become damaged quickly and would need to

be replaced often. An overall problem with wire loops is the system’s

inability to detect vehicles that have high ground clearance and small

vehicles like motorcycles. They also require special inductance measuring

signal processors. The road surface would be physically altered by either

cutting the loops in or attaching the loops. Systems that were evaluated

also required an inductance sensing classifier unit which cost approximately

$1000.

In-Ground Wire Loop

Capability (25/35): The wire loop is a proven technology in the field, having been

employed to detect vehicles at stoplights for years. Unfortunately there are a few

questions behind the system. One is the speed at which the system can operate. We

are unsure as to the ability of the wire loop to detect high-speed vehicles. Also there

are some reliability issues with the wire loop being unable to detect certain vehicles

such as motorcycles. Even though motorcycles may not be very common during an

event, they could prove problematic by injecting erroneous signals into the system.

Ease of implementation (12/20): The system suffers the same shortcomings as the

strain gauge for ease of implementation. The only benefit to the system is that there

may be more off the shelf parts available to assist in decoding the signal generated by

the wire loop. Even so, the loops still require special inductance measuring systems to

process the signal data and this adds to the complexity of the system.

Initial cost (9/15): The price of the system components would be fairly low with the

majority of the costs coming from the signal analyzers. However, the concrete work

would most likely add approximately $2000 to the initial cost.

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Operating / maintenance cost (15/15): This system will require maintenance similar

to that of current technologies that are already at stoplights which is very minimal

because they are buried in the road. This system gets the best score here.

Durability (10/10): This system should be durable enough to survive heavy amounts of

traffic driving over it. This is known due to the ability of current wire loops to survive

large amounts of traffic already. This system also gets the best score here.

Ease of use (5/5): This is a non-portable solution. The operator should only have to

connect the sensors to the system for each event. Because the sensors do not need to

be positioned for each event, this technology receives the highest score.

Total score: 76/100

Portable Wire Loop

Capability (30/35): The portable wire loop is exactly the same as the in-ground loop

with the exception that the portable wire loop is contained in a mat and does therefore

not require any concrete work to install. This also meets the full portability requirements

of the system. High speed vehicles may still present a sensing problem.

Ease of implementation (12/20): This is the same as for the in-ground wire loop

sensors. The system suffers the same shortcomings as the strain gauge for ease of

implementation. The only benefit to the system is that there may be some more off the

shelf parts available to assist in decoding the signal generated by the wire loop. Even

so, the loops do still require special inductance measuring systems to process the

signal data and this adds to the complexity of the system.

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Initial cost (13/15): This system is initially much more cost effective than the in-road

system. The portable sensors cost close to $200 dollars and do not require major

concrete work to install. However, the special inductance analyzer system or systems

will raise this cost, so it doesn’t get the best score here.

Operating / maintenance cost (9/15): This system has a bit more costs associated

with the upkeep of the sensors. Since they will be simply mounted on the road and

driven over, they are not as durable as an in ground wire loop. Repair or replacement

costs will be significantly higher. In addition, the system must be set up in the field

before each event and taken down after each event. This will drive the long term costs

of the system up.

Durability (3/10): The durability of the on-road sensors is significantly less than that of

the in ground system. However, if they are properly positioned so that traffic is not

driving on them they could last a reasonable amount of time.

Ease of use (3/5): This system is a little less user friendly due to the manual

positioning involved in the setup of the sensors. Yet, it is not too technically difficult and

should not require extensive training.

Total score: 70/100

Road Tubes

Operation: Road tubes are often used to count cars and are a proven technology for

that application. They simply consist of rubber tubes which are filled with

air. When a car drives over the tube its internal air pressure increases. An

electronic analyzer converts this pressure increase into signal that can be

used to detect tires passing over the tube. The speed calculating logic that

many of the other systems use would also be employed here. A simple pair

of road tube sensors would be laid across the road at a set distance apart

71

from each other. The time it takes a vehicle’s tires to trigger both sensors

would be used to calculate speed. It would be recommended that they are

placed inside road ramps which are designed to position and protect the

tubes. The ramps also allow the system to measure traffic in multiple lanes

if needed.

Figure 28 - Example of a road tube with mounting hardware

http://products.irdinc.com

Figure 29 - Demonstration of laying road tube inside a flexible road ramp

http://products.irdinc.com

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Pros: This system using existing technology that is relatively cheap to install with

minimal concrete work. The actual road tubes are also cheap to replace at

$45 per 100 feet. These sensors are very reliable for detecting the tires of a

vehicle. In particular, they would detect an axle at a time because either

both of the front tires or both rear tires would hopefully hit the tube at the

same time. The system is also semi-portable.

Cons: Road tubes present many logic problems. For the system to calculate

speed, an individual axle would need to be timed to see how long it takes to

reach the next sensor. If one of these axles was incorrectly detected, it

would throw the system off completely. For example, if the rear axle of a

car was detected at the first sensor and not detected at the second, the

second sensor would be waiting until the next car’s front axle would come

along and trip it. This would completely throw off the timing for the rest of

the analysis unless the logic was reset often. There are other logic

problems as well, such as dealing with vehicle with three axles and vehicles

with trailers. These sensors also often yield faulty signaling if a vehicle is

stopped on top of them. Yet another set back is the amount of time they

would take to setup and take down because the tubes are usually mounted

to the road using concrete nails or adhesive. They would also present

problems for snow plowing and potentially for traction if they are mounted

on a curved section of the road. Systems that were evaluated required a

pressure sensing classifier unit which cost approximately $1000.

Capability (0/35): The road tubes have a difficult time detecting certain vehicles and

higher speed traffic. If the system were to miss an axle, results will be altered terribly

because the system will no longer be able to effectively determine traffic patterns. The

logic involved with axle detection is more complicated and less reliable due to these

problems. The system has difficulty detecting high-speed traffic. Fast moving vehicle

can also present a safety hazard the tube breaks loose from its mounting.

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Ease of implementation (5/20): The system will be difficult for the group to implement.

An extra piece of converting equipment will need to be added to the design to convert

the pneumatic information of the axle counter to an electrical signal so a system could

then decode this signal. In addition to this extra step, creating a reliable control logic

system would be much more difficult for axle detecting than for vehicle detecting.

Initial cost (12/15): The individual component cost of the road tubes is fairly low at $45

per 100 feet. The pressure analyzer and classifier units would cost $1000 for a set of

four tubes. To detect speed at one location on a one lane road at one position would

require two tubes. Special ramps that protect and position the tubes would also be

recommended. These cost approximately $550 for a two-lane wide ramp.

Operating / maintenance cost (5/15): Setup time for this system, repair time, and

storage will increase the long term costs of this system greatly. The system is usually

nailed to the concrete, so after continual setup the road may also need to be repaired.

This problem may be avoided using glue or tape, but these may not hold the sensors as

reliably.

Durability (0/10): The road tubes are not a very durable system and would have a hard

time standing up to the large numbers of vehicles driving over them for an event. They

are designed to be cheaply replaced, so this does help them a little here.

Ease of use (0/5): The ease of use of this system is going to be very low. The road

tube sensors are not that easy to set up. They would need to be nailed into place for

each event which would take a considerable amount of time. Spacing would need to be

specific and they would need to be reliably held down to make sure that a safety hazard

is not created.

Total score: 22/100

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Tape Switches

Operation: Mechanically, they are just switches that are activated by tires running over

them. As far as system logic is concerned, tape switch are very similar to

road tubes. The speed calculating logic that many of the other systems use

would also be employed here. A simple pair of tape switches would be

nailed or adhered to the road at a set distance apart from each other. The

time it takes a vehicle’s tires to trigger both sensors would be used to

calculate speed

Figure 30 - Example of rugged vehicle-axle detecting tape switch

http://www.tapeswitch.com/products

Pros: The sensors are cheap to install because they only need to be attached to

the road. Similar to the road tubes, these sensors would be excellent for

detecting the tires of a vehicle. In particular, they would detect an axle at a

time because either both of the front tires or both rear tires would hopefully

hit the tube at the same time. The system is also semi-portable.

Cons: These sensors cost $315 per switch, so they would be very costly to replace

when they fail. Similar to road tubes, these switches present many logic

problems. For the system to calculate speed, an individual axle would need

to be timed to see how long it takes to reach the next sensor. If one of

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these axles was incorrectly detected, it would throw the system off

completely. There are other logic problems as well, such as dealing with

vehicle with three axles and vehicles with trailers. They would also present

problems for snow plowing and potentially for traction if they are mounted

on a curved section of the road.

Capability (5/35): The tape switches we have the same difficulty detecting certain

vehicles as the road tubes. If the system misses an axle, results will be altered terribly

because the system will no longer be able to effectively determine traffic patterns. The

logic involved with axle detection is more complicated and less reliable due to these

problems. However, these switches are more capable of detecting high speed traffic

than road tubes.

Ease of implementation (10/20): The tape switches will be less difficult than the road

tubes for the group to implement. The extra piece of converting equipment will not be

needed. Creating a reliable control logic system would still be much more difficult for

this axle detecting system than for a vehicle detecting solution.

Initial cost (14/15): The individual component cost of the tape switches is fairly low at

$315 per switch. This makes the initial cost relatively low. Because they are a simple

switch, no special analyzing or converting is needed.

Operating / maintenance cost (6/15): Setup time for this system should be relatively

quick. The tape switch is usually nailed to the concrete, so after continual setup the

road may also need to be repaired. This problem may be avoided using glue or tape,

but these may not hold the sensors as reliably.

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Durability (6/10): Tape switches are designed to be driven over, so they would be

under a lot of abuse. Replacing the sensors could become expensive in the long run.

However, they are specifically design to be driven over, so they should be able to take a

lot of abuse. They are designed to be replaced easily, but their replacement is

significantly more expensive than that of the road tubes.

Ease of use (4/5): The ease of use of this system is going to be fairly low. The tape

switches are easy to glue to or nail to the road, but they would be more difficult to

remove. They are easier to use than road tubes, but not by a lot.

Total score: 45/100

Light Beam

Operation: The operation of this system uses the same speed calculating logic that

many of the other systems use. A simple pair of light beam sensors would

be employed. They would be mounted a set distance apart from each other

on posts on the sides of the road. The time it takes a vehicle to block both

light beams would be used to calculate speed.

Figure 31 - Example of a rugged light beam sensor

http://www.ifmefector.com

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Pros: If this system is properly aimed at approximately a third of the way up a car,

it would be very effective at detecting all vehicles. This system would be

relatively cheap with light beam sensors costing less than $200. Because it

doesn’t count axles, there is not a problem with trailers and tandem axle

vehicles. In addition, this option would not require expensive concrete work

or need to be subject to as much damage by traffic as many of the other

systems. The sensors could be mounted using a quick-release system so

that setup and removal for events would be fast. No special signal

processing is required because they have a simple on/off output.

Cons: The system may have problems dealing with snow, rain or heavy fog. This

system is more fine-tuned than some options, so it may require time to re-

calibrate. If it is not mounted far enough off the road, it could be easily

damaged by vehicles.

Capability (30/35): This system has difficulty detecting multilane traffic. The light

beam detectors may also have trouble in heavy precipitation. Besides, these facts, the

system is portable, safe, reliable and very sensitive. It would be able to detect the

largest amount of vehicles, including motorcycles and vehicles with a high ground

clearance.

Ease of implementation (20/20): The light beam has more sensors act as simple

switches and therefore should be easy to implement. No special signal analysis or

converting should be required. The technology is proven in many other applications

and its implementation here should be no more complicated. Due to its ability to detect

vehicles and not just axles, it is also easier to design a control logic system for. For

these reasons it receives the highest score.

Initial cost (15/15): Rugged light sensors can be purchased for approximately $200 a

piece. These sensors are cheap with regard to other systems and no additional

expensive input to convert the equipment should be needed, unlike the road tube and

78

ground loop systems. Only posts mounted on the sides of the road are required for

installation, so no expensive road work is needed. For these reasons it receives the

highest score.

Operating / maintenance cost (10/15): The setup of this system is rather easy. The

system could be clamped directly to posts installed at the site eliminating the costly

expense of concrete work needing to be done. The system would need to be cleaned

and properly aimed so a little time will need to be spent on this. The expense of setup

should primarily consist of labor cost.

Durability (8/10): The durability of the system is dependant wholly upon the light

sensor that will be selected to implement the system. Rugged light sensors are

available that are durable enough to stand up to severe weather conditions. Because

the system is not mounted on the road it will not be subject to damage from the number

of vehicles that will run over many of the other technologies. Road side equipment

could still be hit by vehicles, but this is would damage any of the other technologies as

well. For these reasons it receives the second highest score.

Ease of use (3/5): The light beam system should be fairly easy to use. All the

installation worker would have to do is clamp the sensor to a pre-installed post and align

the sensor so that it aimed properly. This could be done with a simple test signal. The

mounting equipment on the post could also be designed so that the sensor would be

properly aimed once it is clamped in place. The sensor lenses will also need to be

cleaned before setup in order to provide for the most accurate reading.

Total score: 86/100

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B.2 Datasheet

This set of appendices includes datasheets related to the selected sensor system.

B.2.1 IFM Efector Cable

80

B.2.2 IFM Efector Installation Instructions

81

B.2.3 IFM Efector Reflector

82

B.2.4 IFM Efector Sensor

83

Appendix C - Control System

This set of appendices includes all additional information related to the control system.

C.1 PC-Based Control Technology Evaluation

This section contains appendices which provide additional information about the PC-

based control technology evaluation.

C.1.1 PC-Based Control Technology Criteria Identification

There were several criteria that were used for selecting a PC-based control technology

that would best fit the project. These criteria were chosen to make sure that the control

technology would be able handle the tasks demanded of it.

Capability: This takes into account how well the system can handle the tasks

demanded of it. This will also take into account mobility because this is one of the

design requirements. This category gets the most weight because if the technology

isn’t capable of handling the tasks then it shouldn’t be used.

Ease of implementation: This takes into account how much perceived effort would be

needed to get the control technology running all the tasks that are required of it. This

also includes integrating the control system with the sensors and signs. This category

carries the second highest amount of weight because if the technology is really hard to

implement then it should not be used.

Ease of use: This takes into account how easy it is to use the particular control

system. Can the people operating the control system do so without much trouble, how

great is the learning curve of this new system? Is the interface something they are

familiar with or is it at least something that can easily be learned? Since this is the part

of the system that people will be interfacing with the most it is deemed very important.

84

Initial cost: This entails all costs of setting up the system. This has three major

components the hardware, the software, and the labor to put the system together.

Operating and maintenance cost: This takes into account the cost of having people

use and operate the control system and any setup operations that maybe necessary

each time the system is used. These are the repetitive costs that come about every

time the control system is used.

Durability: This takes into account how well the system can withstand all the abuses it

will incur from the operators and also take into account whether or not it will be able to

withstand the environment it will be running in.

The criteria are weighted as follows:

Capability 35 pointsEase of implementation 25 pointsEase of use 20 pointsInitial costs 10 pointsOperating / maintenance cost 05 pointsDurability 05 points Total 100 points

The weighting was decided based on the overall design objectives, functional

requirements and design constraints. Considerable time was taken to develop a fair

and accurate grading system.

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C.1.2 PC-Based Control Technology Identification and Research

There were many technologies that were identified. They are listed in the tables below.

They include software and both stationary and mobile hardware.

Table 13 - Operating system identification

Technologies Researched Group Familiarity Cost

Hardware Platform

Linux Strong

$162 –Red Hat Enterprise Linux WS V.3 Basic for x86www.newegg.com

Linux can be found on just about any computer platform.

UnixVery Weak although it is similar to Linux

XP Professional Very Strong

$142www.newegg.com X86

Server 2003Weak although it is similar to XP Pro

$499 – 5 Clientwww.newegg.com X86

Mac OS X Strong$129 upgradewww.apple.com Mac

Mac OS X Sever Weak although it is similar to OS X

$499www.apple.com Mac

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Table 14 - Non-mobile hardware platform identification

Technologies Researched Operating Systems Benefits

Dell XP Professional, Server 2003$498-2,500www.dell.com

Mac Mac OS X, OS X Server$1,299-3000www.apple.com

Sun Unix(Solaris), Linux, XP $1,395-1,995www.sun.com

Table 15 - Mobile hardware platform identification

Technologies Research

Group Familiarity Cost Platform

Laptop Very $1039 www.dell.com$999 www.apple.com

X86 or Mac

Intermec CV60 Very $5000 - $10000www.intermec.com

X86: XP Pro, XP Embedded, Windows CE .NET

This section contains all the information gathered about the particular operating systems

and the hardware platforms that run the particular platforms. It also details some mobile

solutions.

Software solutions

The headings below are the operating systems that were discovered as being likely

possibilities for accomplishing the tasks desired.

Linux

Linux would be an excellent choice for communicating with the remote sensors because

it includes a great deal of networking capabilities. Linux can be found on nearly any

hardware platform imaginable. Making it fit to nearly any hardware the team would

decide to use. The support available for Linux is vast on the internet but at times it can

87

be cumbersome finding appropriate drivers to run some pieces of hardware. The

scoring for Linux is as follows.

Figure 32 - Red Hat Linux

http://www.newegg.com

Capability (33/35): Linux is very capable of handling the task of being the operating

system that is used in the control system. It is well equipped to handle communications

but drivers can be hard to come by for some types of hardware.

Ease of implementation (15/25): It is deemed moderately hard to implement

because it can be hard to locate drivers for various pieces of hardware this would make

it very hard to implement. Then, installing the drivers isn’t a trivial operation either. A

great deal of knowledge about the operating system will need to be acquired.

Ease of use (16/20): Linux is fairly easy to use and get used to, but it can be hard to

use at times because it isn’t an extremely mainstream operating system.

Initial costs (10/10): Linux is a very inexpensive operating system. Furthermore it can

run on a Dell system that can be purchased for as little as $498.

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Operating and maintenance costs (5/5): There are relatively no operating or

maintenance costs. The computer must simply be turned on and Linux must be loaded

and running.

Durability (5/5): Linux is a very durable and robust operating system once it is running

it rarely needs to be rebooted.

Total score: 84/100

UNIX

UNIX would be an excellent choice for communicating with the remote sensors because

it entails a great deal of networking capabilities. Plus it has many similarities with Linux

which will make it pretty easy to learn although the user interface can be challenging at

times. Driver availability is of much concern with this operating system even more so

than it is with Linux. This platform is limited to specific hardware namely Sun.

Figure 33 - Solaris a UNIX operating system

http://www.sun.com

Capability (30/35): UNIX is a very capable operating system. It has the built in

communication capabilities. The only question is whether or not all the drivers that are

needed to run the specific hardware will be available.

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Ease of implementation (5/25): UNIX is very different from other operating systems.

The graphical user interface can be hard to use. This makes it very hard to implement

because people don’t have much experience using it.

Ease of use (6/20): UNIX can be very hard to use and get used to. This is due to the

fact that the graphical user interface is not that good. Icons are not placed in familiar

places and the interface is hard to get used to.

Initial costs (5/10): UNIX comes prepackaged with Sun systems. The computers

starting price is $1,395. This places it somewhere in the middle of the pack as far as

price is concerned.

Operating and maintenance costs (5/5): The terminal just needs to be turned on

leaving no real need for any maintenance. Like Linux it is inexpensive to maintain.

Durability (5/5): UNIX is a very stable operating system and will not need to be

rebooted. It can handle the rigors required of it by the project.

Total score: 56/100

Microsoft XP Professional

All of the group members are very familiar with Windows XP. This would make it really

easy to use and setup. This is the operating system that is most desired because there

is such a familiarity with using it. It can handle the communication demands of the

project. The graphical user interface is easy to use due to the high level of familiarity. It

only runs on computers using Intel processors or an Intel compatible processor.

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Figure 34 - Microsoft Windows XP Professional

http://www.newegg.com

Capability (35/35): This is a very capable operating system. It will be able to handle all

the tasks that are required of it. All the needed drivers will be pretty easy to locate and

obtain.

Ease of implementation (25/25): It will be easy to implement this operating system

because many of the needed drivers will be provided. If the required drivers are not

provided they will be easily found on the internet and also will easily be installed.

Ease of use (20/20): XP Professional is very easy to use. Many people are very

comfortable and familiar with this environment.

Initial costs (8/10): While this operating system costs more than some versions of the

Linux operating system it is still very inexpensive. This can be run on a Dell for $498

plus $99 to get XP Professional. This makes it one of the least expensive options.

Operating and maintenance costs (5/5): The operating and maintenance costs are

low because all that is required is that the computer must be turned on and the

operating system loaded and running.

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Durability (4/5): XP Professional is a very durable operating system although it is

known to crash at times.

Total score: 97/100

Microsoft 2003 Server

The team does not have as much experience with this operating system and it goes a

little over the top with features. It is meant to be used as a file server and or an

electronic mail server which is not anywhere near being part of the requirements of the

project.

Figure 35 - Microsoft Windows Server 2003

http://www.newegg.com

Capability (35/35): Much like XP Professional 2003 Server will be very capable of

handling the task.

Ease of implementation (20/25): There are many features that come with 2003 Server

that might make it harder to implement. Also these extra features are not necessary.

Ease of use (18/20): 2003 Server should be relatively easy to use.

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Initial costs (1/10): At $499 2003 Server is one of the more expensive operating

system options. This can be run on a dell that has a starting price of $498.

Operating and maintenance costs (5/5): There isn’t much maintenance that will have

to occur with running this system. All that is required is that the operating system must

be loaded the computer must be turned on.

Durability (5/5): 2003 Server is a very stable operating system and rarely requires

rebooting.

Total score: 84/100

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Mac OS X

Mac OS X is based off of UNIX which in turn means it has great at handling

communications. It also means that it is very similar to Linux. The interface is very

easy to use. There is still matter of whether or not it has the drivers available to handle

the hardware that is being used to communicate with the sensors.

Figure 36 - Screenshot of Mac OS X

http://www.apple.com

Capability (30/35): Mac OS X is a very capable operating system it will be able to

handle all the communications requirements. There is only the question of whether or

not the drivers needed are available.

Ease of implementation (13/25): Since all the required drivers are going to be hard to

come by it is going to be hard to implement.

Ease of use (20/20): OS X is very easy to use. The graphical user interface is very

intuitive and it is also very appealing to the eyes.

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Initial costs (5/10): OS X comes packaged with Macintosh computers with a starting

cost of $1,299. This places it in the middle of the pack as far as price is concerned. It is

right in line with the Sun Microsystems computer running UNIX.

Operating and maintenance costs (5/5): All that is required is that the computer must

be turned on, and the operating system must be loaded and running.

Durability (5/5): OS X requires few if any reboots. It is also a very reliable system.

Total score: 78/100

Mac OS X Server

This probably wouldn’t be a good choice for the operating system because it is more

expensive and probably is overkill much in the same way that Microsoft’s 2003 Server

is. It is still a very capable but the price tag is a problem and the added features are not

needed.

Figure 37 - Mac OS X Server

http://www.apple.com

Capability (20/35): OS X Server comes under the same scrutiny as OS X. It will be

hard to come by all the needed drivers. It can handle the communications just fine. It

will also have many unnecessary features which could get in the way at times.

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Ease of implementation (15/25): Without access to the appropriate drivers it will be

hard to implement the operating system.

Ease of use (17/20): OS X Server is fairly easy to use.

Initial costs (3/10): OS X Server has a price tag of $499 on top of the $1299 it costs to

buy the Macintosh computer. This makes it one of the more expensive options.

Operating and maintenance costs (5/5): There are no major operating or

maintenance costs. All that is required is that the computer be turned on and the

operating system is loaded and running.

Durability (5/5): OS X Server is very reliable. It can also run very well in the

environment it will be operating in.

Total Score: 65/100

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Hardware solutions

In order to run the software specific computers are required. Each operating system

has a platform it needs to run on. The research completed on all the unique types of

platforms required by the operating systems is listed below.

Dell Dimension 2400

Dell computers come with Intel processors making it ideal for running Windows XP. It is

also possible to run Linux on Dell computers. Dell is a very inexpensive solution with a

starting price tag of $498.

Figure 38 - Dell desktop http://www.dell.com

Capability (35/35): The Dell desktop is very capable of handling the tasks required of

it. It comes with USB ports so it will be able to connect the various hardware

components that we need to connect to it.

Ease of implementation (25/25): Implementation will be an easy task. It is just a

matter of finding the proper connectors to connect the desired hardware to the computer

which should be very easy since many devices now incorporate USB.

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Ease of use (20/20): It is very easy to setup and use. Instructions come with it that will

step the user through the setup process.

Initial costs (10/10): This is the least expensive hardware solution that was found

coming in at $498.

Operating and maintenance costs (5/5): The only operating cost would be that of

electricity which isn’t that expensive for running a computer. If any maintenance issues

come up then the technical support for Dell can be called and they will help with any

issues that may occur.

Durability (5/5): This is a very durable product. Rarely are parts defective.

Total score: 100/100

Apple iMac G5

Apple computers are the only computers that run Mac OS X. If Mac OS X is deemed

the best operating system then an Apple will have to be purchased.

Figure 39 - iMac G5 http://www.apple.com

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Capability (35/35): An Apple computer is very capable of handling the tasks required

of it. It comes with USB ports so it will be able to easily connect to various USB

hardware components that may need to be used.

Ease of implementation (25/25): Implementation will be an easy task it is just a matter

of finding the proper connectors to connect the desired hardware to the computer which

should be very easy since many devices now incorporate USB.

Ease of use (20/20): It is very easy to setup and use. Instructions come with it that will

step the user through the setup process.

Initial costs (5/10): Apple computers have a base price tag of $1,299 making it one of

the more expensive options.

Operating and maintenance costs (5/5): The only operating cost would be that of

electricity which isn’t that expensive for running a computer. If any maintenance issues

come up then the technical support for Apple can be called up and they will help with

any issues that may occur.

Durability (5/5): This is a very durable product. Parts are rarely defective.

Total score: 95/100

Sun Blade 150 Workstation

Sun is a very good platform and can run Solaris which is a version of UNIX. These

computers are used predominantly as workstations. This means they offer more than is

required.

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Figure 40 - Sun Blade 150 workstation

http://www.sun.com

Capability (35/35): Sun desktop is very capable of handling the tasks required of it. It

comes with USB ports so it will be able to easily connect to various USB hardware

components that may need to be used.

Ease of implementation (25/25): Implementation will be an easy task it is just a matter

of finding the proper connectors to connect the desired hardware to the computer which

should be very easy since many devices now incorporate USB.

Ease of use (20/20): It is very easy to setup and use. Instructions come with it that will

step the user through the setup process.

Initial costs (4/10): The cost of this hardware solution was found to be close to the

average at about $1395.

Operating and maintenance costs (5/5): The only operating cost would be that of

electricity which isn’t that expensive for running a computer. If any maintenance issues

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come up then the technical support for Sun can be called up and they will help with any

issues that may occur.

Durability (5/5): This is a very durable product. Rarely are parts defective.

Total score: 94/100

Mobile Hardware solutions

What is intriguing about portable technologies is that it would enable the control center

to be relocated depending upon the needs of the event. There are instances where it

maybe advantageous to have the computer control center in a location that is really

close to where the traffic is headed i.e. the parking lots. This will allow for more real-

time input into the system. The people handling the system would be able to make

modifications to the messages based upon observations made about the traffic.

Intermec CV60

The CV60 will be a very nice option in that it can be mounted in a vehicle making it

extremely portable. Furthermore it is extremely rugged it is able to handle temperatures

of (-4 to 122 degrees Fahrenheit) with the solid state version and (-22 to 122 degrees

Fahrenheit) for the extreme operation edition. This computer has a touch screen

making it even easier to use and less cumbersome to learn. It has built in Bluetooth

and 802.11b/g. Since it is rugged it would be able to with stand the abuse put upon it by

the users.

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Figure 41 - Intermec's CV60

http://www.intermec.com

Capability (30/35): The CV60 comes loaded with XP Professional so it is very capable

of meeting the requirements. The required drives might be a little harder to locate

because this is more of specialty item.

Ease of implementation (20/25): It will be very easy to implement this system. It can

be placed just about anywhere. Mounting it in a car might take some time but it should

not present a large problem.

Ease of use (20/20): It will be extremely easy to use. XP Professional is very well

known and this is enhanced by the fact that the CV60 has a touch screen. There will be

no mouse.

Initial costs (0/10): This is a very expensive system to buy. It costs around $5,000-

10,000 making it the most expensive option out of all of them.

Operating and maintenance costs (5/5): This will require little maintenance it will only

need to be turned on and the operating system must be loaded and running.

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Durability (5/5): This is an extremely durable system it can withstand all the

environments that could possibly be thrown at it.

Total score: 80/100

Laptop

The laptop will be much cheaper than the CV60 but it won’t be rugged nor will it have a

touch screen. The laptop can come with built in Bluetooth and 802.11b/g

communications. These options will increase the price but won’t bring it anywhere near

the price of the CV60.

Figure 42 - Gateway laptop

http://www.gateway.com

Capability (25/35): This is a very capable solution but won’t be as well equipped to

handle all the elements that the CV60 can. But it would be a mobile solution which the

desktops are not.

Ease of implementation (15/25): It will be easy to implement especially if it is running

XP Professional.

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Ease of use (16/20): It will be a little bit harder to use simply because mouse

equivalent on a laptop can be a little be harder to get used to and the keyboard is more

compact.

Initial costs (8/10): It will more expensive than its desktop counterparts coming in at

$1039. At this price it is one of the least expensive options.

Operating and maintenance costs (5/5): There are a few more operating costs

because the battery will have to be maintained.

Durability (3/5): It will be less durable because the components of a laptop fall apart

more easily.

Total Score: 72/100

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C.1.3 PC-Based Control Technology Selection

After weighing all the criteria it became apparent which control technology was best

suited for our needs. Windows XP Professional is deemed to be the best fit operating

system because it received the highest point rating. Since XP Professional runs on

computers that have Intel processors it was deemed that a Dell would be the best

hardware solution.

Table 16 - Evaluation of software control technologies

Table 17 - Evaluation of hardware control technologies

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C.2 PLC-Based Control Technology Evaluation

This section contains appendices which provide additional information about the PLC-based control technology evaluation.

C.2.1 PLC-Based Control Technology Criteria Identification

There were several criteria that were used for selecting a PLC-based control technology

that would best fit the project. These criteria were chosen to make sure that the control

technology would be able handle the tasks demanded of it.

Capability: This factor takes into account if the PLC can perform the desired task.

This includes containing the appropriate number of input/output terminals as well as the

communication capabilities. In addition, this factor takes into consideration whether or

not the PLC is fast enough to handle the time frames presented to it.

Ease of implementation: This factor determines how easy the PLC is to design code

for. As always, this is an important qualification in the design process. An easier to

implement system saves both the designers and builders time.

Initial cost: How expensive is the PLC.

Operating costs: This factor examines how much power the PLC uses. Unlike the

other items examined this factor will not expressly be a dollar amount.

Durability: This factor will be used to determine if the PLC can handle rough usage,

constant moving, and the environment it will be used in. This factor is more important

for PLC’s than for other items because they have a lot of sensitive and delicate

components that are going to be exposed to harsh conditions.

Ease of use: How easy is it for another operator to come in and alter the code for the

PLC? Setup time and construction time will also be examined in this section.

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Criteria weighting:

Capability 25 PointsEase of implementation 20 PointsInitial cost 15 PointsOperating costs 10 PointsDurability 25 PointsEase of use 5 Points

Total 100 Points

The weighting was decided based on the overall design objectives, functional

requirements and design constraints. Considerable time was taken to develop a fair

and accurate grading system.

107

C.2.2 PLC-Based Control Technology Identification and Research

Several PLC's were examined to determine the most cost effective, functional, and

reliable system available. Identification, operation, and particular system advantages

and disadvantages will be examined in this section. The research will be covered by

listing how each technology performed based on the criteria that were previously

identified. A final, overall ranking of each technology will also be supplied.

The operation of all of these PLC’s is basically the same. They monitor inputs for

changes and operate a simple ladder logic program which alters the state of their

outputs. In this case, the PLC will be used to monitor the light beam sensors and

operating switches will properly activating the warning system by processing the code

which is included as Appendix A.3. For complete details, the controller datasheets be

found in Appendix C.3.

Allen-Bradley MicroLogix 1000:

Figure 43 - Allen Bradley MicroLogix 1000 PLCwww.ab.com

Pros: A group member has had extensive experience programming on this series

of microcontroller.

Cons: Doesn’t handle cold weather as well as the others

Capability (25/25): This unit provides all required capability.

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Ease of implementation (20/20): Since a group member already has considerable

experience with Allen-Bradley MicroLogix controllers, this unit gets the full points for this

area.

Initial cost (5/15): The base price for this unit is low at $170, but the $500

programming software is very expensive.

Operating cost (5/10): The unit fails to receive full points in this area because it

requires a heater to work in the environment. This is important because it will increase

the long term costs associated with the batteries for the unit and decrease operating

time per charge.

Durability (10/25): The unit does meet the necessary humidity specifications found in

Iowa. In addition, the shock specifications of this unit are high enough to survive any

physical abuse the unit may receive during transport and setup. Unfortunately, this PLC

is very poor at handling cold weather and will require an enclosure heater for winter use.

Ease of use (5/5): This PLC is much like all of the other PLC’s in terms of being easy

to use.

Total Score: 70/100

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Mitsubishi Alpha Series

Figure 44 - Mitsubishi Alpha PLCwww.electrodepot.com

Pros: This PLC meets all of the requirements for weather, and durability.

Cons: This was the most expensive PLC that was examined. In addition, no group

member has any experience programming on this type of PLC.

Capability (25/25): This unit provides all required capability

Ease of Implementation (0/20): No member of the group has any experience with

programming a Mitsubishi Alpha Series PLC.

Initial Cost (10/15): At $200 The Alpha is slightly more expensive than the Allen

Bradley PLC. However, the programming software is much cheaper at $200.

Operating Cost (10/10): This unit uses slightly less power than the Allen Bradley unit

and therefore reduces the long term costs. More importantly, the unit meets necessary

operating temperatures so it will not need a heater to operate.

Durability (25/25): This unit has durability ratings much like the Allen Bradley and has

much colder minimum operating temperature.

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Ease of Use (5/5): This PLC is much like all of the other PLC’s in terms of being easy

to use.

Total Score: 75/100

GE Fanuc VersaMax Nano series

Figure 45 - GE Fanuc VersaMax Nanowww.geindustrial.com

Pros: This PLC is very compact.

Cons: It does not meet the necessary requirements for temperature and durability.

No group member has any experience programming on this type of PLC.

Capability (25/25): This unit provides all required capability.

Ease of implementation (0/20): No member of the group has any experience with

creating ladder logic on the GE Fanuc Series PLC.

Initial cost (15/15): This PLC can be purchased with basic programming software and

cable as a starter kit for under $400. This was found to be the cheapest solution.

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Operating cost (5/10): The temperature ranges for this PLC would require it to have a

heater. This is important because it will increase the long term costs associated with

the batteries for the unit and decrease operating time per charge.

Durability (5/25): This PLC has durability ratings worse than that of the Allen-Bradley

PLC.

Ease of use (5/5): This PLC works in much the same way as the other PLC’s that were

found.

Total Score: 55/100

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C.3 Datasheet

This set of appendices includes datasheets related to the control system.

C.3.1 Allen Bradley MicroLogix 1000 PLC

24V dc Sensor Power 200 mA max. with 200 F capacitive load max. (for 1761-L10BWA, -L16NWA, -L16BWA, -L20BWA-5A, and -L32BWA only)

Power Cycles 50,000 minimum Operating Temperature

Horizontal mounting 0…55 °C (32…131 °F) Vertical mounting 0…40 °C (32…104 °F)

Storage Temperature -40…85 °C (-40…185 °F) Humidity 5…95% (without condensation) Shock, Operating 10 g peak acceleration (7.5g DIN rail mounted)  (11±1 ms duration), 3

times each direction, each axis Shock, Non-Operating 20 g peak acceleration (11±1 ms duration), 3 times each direction, each

axis Vibration, Operating 5 Hz to 2 kHz, 0.381 mm (0.015 in) peak-to-peak / 2.5 g panel mounted ,

1hr per axis Vibration, Non-Operating 5 Hz to 2 kHz, 0.762 mm (0.030 in) peak-to-peak / 5 g panel mounted, 1hr

per axis Terminal Screw Torque 0.9 N-m maximum (8.0 pound-inch) Electrostatic Discharge IEC801-2 @ 8 KV Radiated Susceptibility IEC801-3 @ 10V/m, 27…1000 MHz

3V/m, 87…108 MHz, 174…230 MHz, and 470…790 MHz Fast Transient IEC801-4 @ 2 KV Power Supply, 1 KV I/O Isolation 1500V ac Memory Type EEPROM Memory Size 1K words (approximately 737 instruction words, 437 data-table words) Timers/Counters, Max. 40 timers; 32 counters (fixed) Program Scan Time/Kword, Typical

2 ms

I/O Scan Time, Typical 0.21 ms Communication Port RS-232-C (Can be configured for communication through 1761-NET-AIC

in a DH-485 network)

Cat. No. I/O Digital Inputs

AnalogInputs

Digital Outputs

Analog Outputs

Real Input Power

1761-L16BWB 16 10 inputs24V dc sink/source

0 6 contact outputs

0 5W @ 24V dc

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Physical Specifications

Cat. No. Weight:kg (lb)

Height:mm (in)

Width:mm (in)

Depth:mm (in) 

1761-L10BWA 0.2 (0.5) 80 (3.15) 120 (4.72) 40 (1.57) 1761-L10BWB 1761-L10BXB 1761-L16AWA 0.4 (0.8) 133 (5.24) 73 (2.87) 1761-L16BWA 120 (4.72) 1761-L16NWA 1761-L20AWA-5A 0.6 (1.2) 200 (7.87) 1761-L20BWA-5A 1761-L20BWB-5A 1761-L32AWA 1761-L32BWA 1761-L32AAA 1761-L16BBB 0.2 (0.5) 120 (4.72) 40 (1.57) 1761-L16BWB 1761-L16NWB 1761-L32BBB 0.4 (0.8) 200 (7.87) 1761-L32BWB   

Analog Input Specifications

Voltage Range ±10.5V -1LSB Current Range 0…20 mA -1LSB Data Format Natural binary 16-bit signed integer Voltage Input Impedance 210 kW Current Input Impedance 160 kW Resolution 16 bits  Overall Accuracy 0…55 °C ±0.7% of full scale     Also a function of the input filter selection.

Analog Output Specifications

Voltage Range 0…10V -1LSB Current Range 4…20 mA -1LSB Data Format Natural binary 16-bit signed integer Step Response 2.5 ms @ 95% Load Range 0…500 Current Output Coding (4…20 mA -1LSB, 0…10V -1LSB)

0…32,767

Resolution 15 bits Overall Accuracy 0…55 °C ±1.0% of full scale   

Source: www.ab.com

114

C.3.2 GE Fanuc Nano and Micro PLC’s

115

116

Source: www.geindustrial.com

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C.3.3 Mitsubishi Alpha

Alpha™  Programmable Controller, 8 Inputs, 6 Outputs    Model:  AL2-14MR-D

  $259.99 

Product Information

Software Specifications

Application Examples

Hardware   Manual

Program Manual  

Features Extra-big backlit LCD display   8  Inputs, 6

Outputs Unlimited applications Program directly on the unit, or via optional VLS

Windows software   Built-in LCD screen operator interface functions   Graphical "function block" style programming, with

drag and drop icons   Integrated calendar/clock function.  Summer time set Real Time Clock with 4 digit year.  Function blocks, such as timers, counters, latch,

compare, etc. Can replace a multi-channel real-time clock   Easy to program scheduling functions   AS-i interface options Optional  DC Power supply

Optional  Expansion: Analog output   Relay intput   Digital input

Specifications   Alpha™ Programmable Controller Analog or digital inputs  Input can be "on/off" or 8-bit, 0-10 VDC  Input impedance 142 kOhm  Response time Max 10 ms Relay Output 8 Amp  250 VAC RS232 Interface    Dimensions 4.91 x 3.5 x 2.16 inch (124.6 x 90 x 55 mm) Operating temperature range -12 to 132°F ( -25 – +55

°C ) UL, listed, CE approved

Remote access

118

  

   Alpha™  Programmable Controller, 6 Inputs, 4 Outputs  

Model:  AL-10MR-D

$199.99  

Product Information

Software Specifications

Application Examples

Hardware   Manual

Program Manual  

Features Very Compact Size   Unlimited applications Program directly on the unit, or via optional VLS

Windows software   Built-in LCD screen for programming panel or

operator interface functions   Graphical "function block" style programming,

with drag and drop icons   Integrated calendar/clock function. Summer

time set Real Time Clock with 4 digit year   Function blocks, such as timers, counters,

latch, compare, etc. Can replace a multi-channel real-time clock   Easy to program scheduling functions   AS-i interface options

Remote access        Specifications   Alpha™ Programmable Controller

Analog or digital inputs  Input can be "on/off" or 8-bit, 0-10 VDC  Input impedance 142 kOhm  Response time Max 10 ms Relay Output 8 Amp  250 VAC RS232 Interface    Power 24.VDC 7.Watts, optional  DC Power

supply Dimensions 2.7 x 3.5 x 2.16 inch (71.2 x 90 x 55

cm)

UL, listed, CE approved

Source: www.electrodepot.com/micro.htm

119

Appendix D - Communication System

D.1 Communication Technology Evaluation

This section contains appendices which provide additional information about the

communication technology evaluation.

D.1.1 Communication Technology Criteria Identification

There were several criteria that were used for selecting a communications technology

that would best fit the project. These criteria were used to insure that the

communications technology would be able to handle the task demanded of it.

Capability: This takes into account how well the system can handle the tasks

demanded of it. This category gets the most weight because if the technology isn’t

capable of handling the tasks then it shouldn’t be used.

Ease of implementation: This takes into account how much perceived effort would be

needed to get the communications technology function as needed. This also includes

integrating the communication system with the control system and with the message

system. This category carries the second highest amount of weight because if the

technology is really hard to implement then it should not be used.

Ease of use: This takes into account how easy it is to use the particular

communication system.

Initial cost: This entails all costs of setting up the system. This has three major

components the hardware, the software, and the labor to put the system together.

Operating and maintenance cost: This takes into account the cost of having people

use and operate the control system and any setup operations that maybe necessary

120

each time the system is used. These are the repetitive costs that come about every

time the control system is used.

Durability: This takes into account how well the system can withstand all the abuses it

will incur from the operators and also take into account whether or not it will be able to

withstand the environment it will be running in.

The criteria are weighted as follows:

Capability 35 pointsEase of implementation 25 pointsEase of use 20 pointsInitial costs 10 pointsOperating / maintenance cost 05 pointsDurability 05 points Total 100 points

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D.1.2 Communication Technology Identification and Research

There were two major types of communication that were identified. The first was radio

communications and cellular communications.

Cellular:Cellular communications looked to be very good at first because it would be able to

communicate to any location with cellular service. This was quickly dispelled by the fact

that there were multiple companies that offered solutions that under the current industry

standard would not be compatible with the display system. This was due to the fact that

the standard communications protocol (NTCIP) was not very standard at the time this

research was conducted. The other major hurdle was the fact that the team would have

to write the protocol to interface with the devices that were in communication. This is

such a daunting task that cellular communications was eliminated as a possible

solution.

Radio:Radio communications has to offer several advantages over the cellular

communications. There would be no need to write a communications protocol. Also

units were found that could easily be interfaced with a PLC via contact closure.

Therefore, radio communications was selected as the best technology for handling the

communications.

Radio Communications Technology Identification and ResearchSeveral radio communication technologies were identified and researched.

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Encom Wireless (Model # 7314):

Figure 46 - Encom wireless communication systemwww.encomwireless.com

Capability (35/35):It is fully capable of communicating with a remote receiver up to 20 miles away line-of-

sight. It operates with a contact closure to turn on and off making it fully capable of

interfacing the light system.

Ease of implementation (17/20):There is minimal programming involved in setting up the radio to act as a transmitter or

a receiver. Once the radio has been set it will stay set allowing for a one time setup

needed. It also includes software for future programming if extended uses are needed.

This allows for expanding the scope of the project to interface with multiple receivers

and allows the receivers to send an acknowledgement if there is ever a need for this in

the future.

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Initial cost (12/15):The costs involved with this are the cost of the radio which is $900. Two radios would

be required one to act as receiver and one as a transmitter. This includes the casing for

making the radio more rugged. In addition to this there may be the need for Yagi

directional antennas to overcome any line-of-sight barriers. The estimated price from

Encom was $1275 for each radio with antenna and cabling.

Operating / maintenance (15/15):The operating conditions are for the radios are to industry standard including -40 – 80

degrees Celsius. Encom designs systems specifically for use with traffic and have

designed systems using the same type of radios in Omaha and Lincoln Nebraska which

have similar weather conditions. The radios are also able to be managed through

software which allows them to be reprogrammed given a problem.

Durability (10/10):The Encom radios are durable to industry standard and the NEMA 4X aluminum

weather casings make them extremely durable.

Ease of Use (5/5):All of these factors make the radios extremely easy to use. They have 4 inputs that

take an open or closed signal depending on what is needed so they will interface with

the PLC very well.

Total Score: 94/100

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Remote Control Tech Wireless Switch System (Model # 01210):

Figure 47 - Remote Control Technology transmitter modulewww.remotecontroltech.com

Figure 48 - Remote Control Technology receiver modulewww.remotecontroltech.com

Capability (35/35):The Wireless Switch System by Remote Control Tech is very capable of handling the

communications. The range of the radio is up to 5 miles, which is adequate for distance

between the sensors and the message system. It is designed specifically for PLC input

on the transmitter and contact closure output on the receiver. This makes it ideal for the

task.

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Ease of implementation (20/20):The Wireless Switch System was designed to interface with a PLC, which will make it

really easy for it to be implemented. The receiver and the transmitter are already

configured to communicate with each other so no protocol or programming is needed in

order to get the two ends to communicate. The receiver also has contact closures that

are powerful enough to power a flashing light. The output voltage is 12Vdc and up to 1

amp of current can flow per output.

Initial cost (5/15):It costs $3300 for the receiver and transmitter. This is more expensive than the other

systems that were identified. Optional solar panels (#09613) can be purchase starting

at $800(10 Watts) up to $2700(55 Watts).

Operating/maintenance (15/15):This system can operate in -40 to 140 degrees Fahrenheit weather. There is no need

for any regular maintenance.

Durability (10/10):It is very durable. The transmitter and receiver are housed in an aluminum case, which

is very rugged. It is designed for industrial environments.

Ease of Use (5/5):It will be very easy to use. All that has to be done is connect the transmitter to the PLC,

connect the receiver to the display system, and connect both to a power source.

Total Score: 90/100

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D.2 Datasheet

This set of appendices includes datasheets related to the communication system.

D.2.1 Encom7318

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D.2.2 Remote Control Tech Wireless Switching System

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Appendix E - Display System

E.1 Display Technology Evaluation

The display system is the part of the overall design that pertains to alerting the motorists

of the potential dangers ahead. In the following section, the potential display systems

will be identified and evaluated.

E.1.1 Display Technology Criteria Identification

This section will detail the criteria used to narrow the warning system selection down to

the final optimal solution. The following criteria are going to be used to determine the

selection of the warning system.

Capability: This factor takes into account the system’s ability to meet the design

objectives, functional requirements and design constraints of the project. The reliability,

safety, impact and expandability of the system are key components here.

Ease of implementation: Ease of implementation is the next most important criteria.

Due to the limited time constraints of this project, the group will attempt to employ as

many “off-the-shelf” parts as possible. The amount of difficulty involved with designing

the system using the given technology will be examined.

Initial cost: Initial costs include the price of components for the unit, assembly, and

installation costs.

Operating / maintenance cost: This factor deals with setup of systems that have to be

installed and removed before and after each event. Also this factor deals with the

maintenance costs of each unit. This includes storage and basic maintenance to the

unit.

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Durability: Durability is another important factor in choosing a warning technology.

The system needs to be able to withstand all of the natural elements and in addition

survive in a high traffic area.

Ease of use: Ease of use is an important factor when considering the operation of the

warning devices. It is undesirable to need to train people how to use a difficult system.

It is also best to have the system be easy to setup due to time constraints before and

after an event. Therefore, even if systems are equal based on a sum of the initial and

operating costs; this factor accounts for the advantage of having an easy to use

solution.

These criteria are weighted as follows:

Capability 35 PointsEase of implementation 20 PointsInitial cost 15 PointsOperating / maintenance cost 15 PointsDurability 10 PointsEase of use 05 Points_______________________________________Total 100 Points

The weighting was decided based on the overall design objectives, functional

requirements and design constraints. Considerable time was taken to develop a fair

and accurate grading system.

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E.1.2 Display Technology Identification and Research

Portable Sign with Flashing Lights

A portable sign with flashing lights was the simplest warning technology to be

evaluated. The sign would read “slow traffic ahead when flashing.” The flashing lights

would be mounted to the sign and they would be switched on by the control system

when a slow traffic condition is detected. The sign could also be permanent if so

desired to reduce initial cost. The cheapest portable sign would be of the type that is

setup and held in place with sand bags. An easier to move solution would be to mount

the sign on a trailer. This would be more expensive, but would decrease setup time.

Figure 49 - Example of a trailer-mounted sign with flashing lightshttp://www.irdinc.com

For the evaluation, the cheap, portable, sand-bag anchored solution will be evaluated.

This was chosen because the increase in cost for trailer system would hurt this option.

Capability (30/35): This system would meet the portability requirements. The flashing

lights would also provide for a high-impact notification. However, the message can not

be changed to provide more information.

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Ease of implementation (20/20): This system is the easiest to implement. The reason

for this is its simplicity. A simple on/off signal needs to be sent to the sign. This is the

easiest operation. Controlling flashing lights is also the simplest technology.

Initial cost (15/15): This system is the cheapest alternative to purchase. All that is

needed is a sign, a supporting metal frame, flashing lights, a communication system

and a control system.

Operating / maintenance cost (8/15): This system would have some operating cost

associated with the fact that it would be the most difficult to setup. Workers would need

to assemble the sign and position it. Sand bags or another holding device would be

needed to anchor the sign in place.

Durability (7/10): The system itself should very durable. This is because it should not

have any complex or sensitive parts. The lights may need occasional replacing, but this

can be significantly reduced by using LED’s (light emitting diodes) in place of normal

incandescent. The system will most likely sustain most of its damage in the moving and

setup/removal processes.

Ease of use (3/5): This system the not very easy to setup due the need for partial

assembly and sand-bag anchoring.

Total score: 83/100

Portable Message Board

Portable, electronic message boards are also common ways of alerting motorists to

potential dangers. These boards can display a variety of messages and can be

programmed to display a specific message. They are operated via cellular

communications. These message boards are more functional than the simple sign with

flashing lights, but they are also significantly more costly at over $15,000.

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Figure 50 - Trailer-mounted electronic message board

http://www.nationalsignalinc.com/

For this option, it will be assumed that the sign would be rented or provided by the DOT.

This is done because it would be a poor use of funds to buy one of these expensive

signs and only use it for this system. To justify this expenditure, the traffic monitoring

system would most likely need to see more use and be applied in multiple locations.

Capability (35/35): Message boards are the most capable warning system. In addition

to being very portable, they have a high impact. More information can also be shown

with the changeable display.

Ease of implementation (5/20): The message board would not be easy to implement

because the communication system is very complex. Different manufactures use

different communication protocols. A standard has been started, but it is not fully

accepted yet. A computer based control system with complex software would be most

likely be needed to communicate with the message board.

Initial cost (15/15): For this technology, it is assumed that the system will be provided,

so the up front cost should be minimal.

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Operating / maintenance cost (0/15): This system has the worst operating cost. This

is because the system would need to be rented for events. In addition, it would still

need to be hauled and setup for each event.

Durability (9/10): The message boards should be relatively durable. They have

sensitive electronics, but they are field proven and should not present any problems

here.

Ease of use (3/5): This system is easy to transport because it is trailer mounted.

Unfortunately, unless the same sign can always be used, programming may need to be

done in order to get the proper messages to display.

Total score: 67/100

Radio Broadcast

This solution is quite different from the other two. Radio broadcasts are commonly used

on highways to inform drivers. Signs are posted that state the purpose and frequency

of the broadcast. Short range systems can be purchased without the need for extensive

design. They could be made portable to reduce wear from the weather, but they are

usually mounted to poles. The messages could be recorded and played by the overall

control system. Different messages would be sent depending on the state of traffic flow.

The central server would select which message should be played. In addition, a live

transmission is available in case of an extremely dynamic traffic situation or special

circumstance. This system works best when used in conjunction with other message

systems.

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Figure 51 - Pole-mounted radio broadcast transmitterhttp://www.highwayinfo.com

Figure 52 - Possible radio notification signhttp://www.highwayinfo.com

Capability (15/35): This form of communication can provide the detailed information to

motorists. This would be useful in rerouting traffic and warning motorists well in

advance of traffic situations. Unfortunately, this system is not very effective on its own

as many drivers tend to ignore radio station signs.

Ease of implementation (20/20): This is a fairly easy system to implement. Pre-

recorded messages can be selected by cellular technology. The “all in one” unit

eliminates assembly, programming, and communication issues.

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Initial cost (5/15): This will be a fairly costly system to implement. The broadcasting

units are quite expensive but include the required FFC radio license.

Operating / maintenance cost (15/15): Since the system is solar powered and does

not need to be maintained after it is mounted and setup its operating and maintenance

costs are near zero.

Durability (10/10): The system meets all necessary temperature requirements and is

resistant to all forms of weather.

Ease of use (5/5): This system is easy to use. After the system is mounted, all that

needs to be done is for the server to select the message that will be transmitted.

Total score: 70/100

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E.2 Datasheet

This set of appendices includes datasheets related to the display system.

E.2.1 OkSolar Flashing Light System

Applications: 24-Hour Flashing Beacon Systems School Zone Flashing Beacon Systems with Programmable Time Control Speed Awareness Displays Firehouse Entrance / Exit Warning Beacons Intersection / Crosswalk Warning Work Zones Sharp Curve Warning Factory/Plant/Facility Entrance Warning Railroad warning Ice on bridge warning

Low water crossing

Features: Low-Cost Installation -- Easily and Quickly Deployed in Any Location LED Beacons - Long-Life with Extremely Low Power Consumption Virtually Maintenance-Free Design Vandal and Theft Resistant Components and Hardware 25-Year Warranty on Solar Modules (Optional) Unbreakable Solar Modules (Optional) Remote Control Activation.

3 day’s worth of Backup energy for cloudy days

Basic System includes

Led Lamps. o Meets ITE Chromatic and Visibility Requirements o Low power usage. o Long life, virtually no maintenance.

Solar Panel. Structure for solar panel

o Pole Top mount o Adjustable 0-90 horizontal and 360 about pole.

Charge controller. Security breaker. Aluminum Enclosure.

o Vented door has keyed. o locking mechanism o Vandal-Resistant

Batteries: o Long-Life, Deep-Cycle. o Maintenance-Free.

Activation Switch On/Off: standard Key switch.

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Optional

2 Heads Led Lamps o Alternative flashers Item#

Pole / Base: Item# 170861 o 15 feet and Base Square Aluminum with Plastic door 5335 and Break way collar for heavy systems.

Activation: o Timer Item Numbers:

# 160833 # 160834

o Optional Wireless: Key Cain distance up to 200ft. Item# 160836 Wireless up to 5 miles. Pager activated Satellite Activation

Energy Plug-In Item# 160804 o Increase the back up energy for areas of Low solar radiation or cloudy days to 7

Sign Items: o Item# 170880 o Item# 170882 o Item# 170844

o We can custom make any type

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E.2.2 Highway Information Systems Radio Broadcaster

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E.2.3 National Signal Portable Message Board

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Appendix F - System Construction, Setup, and Operation

F.1 Diagnostic Testing Procedure

The system has been designed with a diagnostic setting. Use the selector switch to

enter this mode. In this mode fast traffic is counted as a traveling the 5.5ft in 2 seconds

while slow traffic takes more than 4 seconds. This has been done to allow manual

testing.

To check proper system operation, follow these steps:

Press the Reset button to clear all counters

Pass your hand in front of BEAM1, wait 5 seconds and pass your hand in front of

BEAM2. This simulates a slow car.

Repeat previous step and watch to see if each beam’s indicator light is triggered

followed by the warning indicator. This simulates a second slow car and should

cause the system to trigger the warning state.

o If one of the sensor indicator lights doesn’t flash and the warning light

does not come on, the sensor is not detecting properly and needs to be

calibrated or replaced.

o If one or both of the indicator lights do not flash, but the warning indicator

is activated; the lights are either burned out or not connected and should

be checked for voltage.

o If the warning indicator is not activated it too may be burned out or

disconnected and should be checked for voltage.

o If the warning display system lights are not activated, the communication

transmitter input should be checked for voltage. If it is present, there is

most likely a communication block.

Pass your hand in front of BEAM1, wait 1 second and pass your hand in front of

BEAM2. This simulates a fast car.

Repeat previous step, twice. This simulates a second and third fast car and

should cause the warning to be disabled.

o If this test procedure fails, try the test process over again.

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o If it fails again, there may be a more serious problem with the wiring or controller that should be addressed.

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F.2 Complete System Comparison

While researching technology options, other highway traffic monitoring systems were

found that provided the same functionality as the system that has been designed by this

team. In this section, these systems are identified and evaluated.

F.2.1 Complete System Criteria Identification

This section details the criteria used to evaluate the complete traffic monitoring systems.

The following criteria are going to be used.

Capability: This factor takes into account the system’s ability to meet the design

objectives, functional requirements and design constraints of the project. The accuracy,

reliability, safety and expandability of the system are also key components here.

Initial cost: Initial costs include the price of components, assembly, and installation

costs.

Operating / maintenance cost: This factor deals with setup of systems that have to be

installed and removed before and after each event. This includes storage and basic

maintenance to the unit.

Durability: Durability is another important factor in choosing a system. It needs to be

able to withstand all of the natural elements and in addition survive thousands of

vehicles driving over or past it.

Ease of use: Ease of use is an important factor when considering the operation of the

overall system. It is simply undesirable to have to train people how to use a difficult

traffic system. It is also best to have the system be easy to setup due to time

constraints before and after an event. Therefore, even if systems are equal based on a

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sum of the initial and operating costs; this factor accounts for the advantage of having a

system that is easy to use.

These criteria are weighted as follows:

Capability 35 PointsInitial cost 35 PointsOperating / maintenance cost 15 PointsDurability 10 PointsEase of use 05 Points_______________________________________Total 100 Points

The weighting was decided based on the overall design objectives, functional

requirements and design constraints. Because the systems varied so greatly in

functionality, they were not scored and eliminated as was the process for component

technology selection. Instead, these criteria were used to evaluate each system and

create recommendations for each system’s application. If further research were to be

conducted, these criteria could be used to make a decision between any systems that

have similar functionality.

F.2.2 Complete System Identification and Research

During the identification process, two additional systems were found. These systems

use different technologies and therefore have different advantages and disadvantages.

In the following, both of these systems will be described.

Nu-Metrics:Nu-Metrics is a company that has developed an in-road traffic monitoring system. Their

system uses Groundhog® road analyzers which detect vehicles with the use of magnetic

fields. These are similar to wire loops, but these sensors are only six inch diameter and

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are placed into the concrete or asphalt by drilling out a core. Once they are positioned,

they can also be easily repaired or replaced. This is done by simply removing their

water proof covers. The picture below shows the sensor unit.

Figure 53 - Nu-Metrics magnetic sensor unit

http://www.nu-metrics.com

These sensors transmit data wirelessly to a receiving station that can be up to 600 feet

away (200 feet is recommended). The receiving unit is called the radio frequency

module (RFM). Here, the data is collected from the sensors and can be transmitted

further using 2.45 gigahertz spread spectrum communication. The RFM base can

transmit up to 20 miles (line of sight) to another base. At the base, the information from

the sensors can be processed using a computer. Software can be purchased to

monitor the traffic flow. Vehicle count, speed and length can all be monitored.

Unfortunately, this system’s primary use is monitoring and recording data. A system

that monitors data and then controls a display system is what is needed. The design

engineers at Nu-Metrics were working on developing a system that met this project’s

requirements. However, work was discontinued with Nu-Metrics because of the cost

involved in order to develop a system that met the specifications.

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The basic design would include one sensor that would be positioned on the exit ramp

near the merging end. This sensor would communicate with a RFM station which would

in turn communicate with a permanent warning sign that has controllable flashing lights.

The sign would have a message like “slow traffic ahead when flashing”. Software would

be developed that would use the speed data from the sensor to control the flashing

lights on the sign. When the speed reached a set low limit around 10 MPH the flashing

lights would be turned on.

This system would not be portable. The sensors are mounted in the road. The RFM

unit is usually pole mounted on the side of the road with an antenna and solar panel for

power. The sign could be mobile, but by this point it would just be cheaper to install a

permanent sign so that setup cost can be practically eliminated.

Because of the amount of effort that will be put into this design and quoting process, this

system has not been further developed. If funding for additional research could be

obtained, the system design could continue in more detail. The engineers at Nu-Metrics

would completely design the system and send drawings, schematics, parts lists and

exact prices.

International Road Dynamics:International Road Dynamics (IRD) is a company that has developed a non-intrusive

traffic monitoring system. Their system is completely mobile and meets all of the

requirements and ideals of the highway traffic monitoring system this team designed.

The system uses a microwave radar device to detect speed. In the two pictures below,

the radar device is the white box that is mounted to the side of the trailer sign. The

sensor is mounted on a trailer with the control logic system and communication system.

This system is all powered by batteries that are charged by a solar panel. An antenna

is used to transmit commands to a mobile sign that is located up to a mile away (line of

sight). This sign would be similar to those shown below, only the message would read

something like “slow traffic ahead when flashing”.

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Figure 54 - IRD trailer mounted warning sign with flashing lights

http://www.irdinc.com

Figure 55 - Another IRD warning sign with flashing lights

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For this application, only one of the mobile sign trailers and one sensor / control trailer

should be needed. The sensor trailer would be setup near the middle of the exit ramp.

Speed would be precisely monitored from here. Once the average speed drops below a

set point, the flashing lights on the sign would be activated.

Because this highway traffic monitoring system would only need minimal modification to

fit the specified application, a rough estimate has already been received. This estimate

is for a three trailer system that would consist of one sensor trailer, one sensor/sign

trailer, and one sign trailer. The first sensor trailer would be located near the merging

section of the exit ramp. It relay information back to the next trailer which would contain

a sign and sensor. This second trailer would be located at the exit off of the highway.

The sign here would be controlled by the first sensor and display a warning when exit

ramp traffic slows down. The sensor on this second trailer would be used to send a

message to the third trailer which would consist of only a sign. This sign would warn

when traffic actually started to slow on the highway.

Initial deployment: $10,000 - $20,000 (for a three trailer system)

This includes the cost of designing the system to meet area specific needs. Also

included in this cost is delivery and system operation training.

Price per trailer unit: $10,000 - $15,000

This price will vary depending on what equipment is installed on each trailer. The sign

trailer is the cheapest. After that, the sensor trailer is second. Finally, the sensor / sign

trailer is the most expensive, as expected.

Total rough estimate: $38,000

If the less complicated dual-trailer system is used the price will be significantly reduced.

This system would have a sensor trailer and a sign trailer. The sensor system would be

mounted on the exit ramp near the highway. It would use the collected speed

information to control the warning sign trailer that would be mounted about a half mile

down the highway. With the rough figures, a deployment cost of approximately $15,000

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could logically be used for this less complicated system and the unit cost would be

around $10,000 for the sign trailer and $13,000 for the sensor trailer which would give a

very rough estimate of $38,000.

These systems can be modified for individual applications even further than the basic

control logic and location. Electronic message boards can be used instead of flashing

lights. The system can transmit data wirelessly to a computer to update a website that

displays current traffic information. A paging ability can also be added that allows the

system page or e-mail someone during a set condition. For example, if ramp traffic

came to a complete stop, the highway patrol could be notified. In addition to this

monitoring system, a video surveillance trailer could be positioned with the other trailers

to feed video to the website. This would allow for even more monitoring capability.

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