Traffic Engineering

Institute of Traffic Engineers (ITE) defines traffic engineering as a subset of transportation engineering.

The definition given is as follows: “Traffic Engineering is that phase of transportation engineering

which deals with the planning, geometric design and traffic operations of roads, streets and highways,

their networks, terminals, abutting lands, and relationship with other mode of transportation”.

The objective of traffic engineering is to provide for the safe, rapid, comfortable, efficient, convenient,

and environmentally compatible movement of people, goods, and services. The revolution in the

automobile industry and liberalized economy has led to tremendous increase in the vehicle ownership

levels. With the development of urbanization and motorization, the imbalanced contradiction of urban

traffic between supply and demand becomes increasingly sharp. Traffic congestion has become a serious

“urban illness”, and it results in problems such as travel time delay, increase of traffic accidents, rise of

fuel depletion, survival environmental degradation and so on. It severely affects the city’s normal

function and its sustainable development. The scope of the traffic engineering lies here. Traffic

engineering improves the traffic performance of road network and terminals with the help of systematic

traffic studies, detailed analysis and also with effective applications. It also includes planning, geometric

design, regulation and control of various traffic operations.

1.1 Elements of Traffic Engineering

There are a number of key elements in traffic engineering.

• Traffic studies and characteristics

• Performance Evaluation

• Facility Design

• Traffic Control

• Traffic Operations

• Transportation System management (TSM)

• Integration of Intelligent transportation system technologies (ITS)

Traffic studies and characteristics: Involves measuring and quantifying various aspects of highway

traffic. Studies focus on data collections and analysis that is used to characterize traffic includes traffic

volumes and demands, speed and travel time, delay, accidents, origins and destinations, modal use and

other variables.

Performance Evaluation: is a means by which traffic engineers can rate the operating characteristics of

individual sections of facilities and facilities as a whole in relative terms. Such evaluation relies on

measures of performance quality referred as “Level of service”. Different classes are there in level of

service, starting from L.O.S A to L.O.S F (A-very good, F- failure on some level).

Facility Design: Involves traffic engineers in the functional and geometric design of highways and other

traffic facilities. They are not directly involved in the structural design of highway facilities but have

some appreciation for structural characteristics of their facilities.

Traffic control: central function of traffic engineers and involves the establishment of traffic regulations

and their communication to the driver through the use of traffic control devices, such as signs, markings

and signals.

Traffic Operations: involves the measures that influence overall operation of traffic facilities, such as

one-way street systems, transit operations, curb management and network control systems.

Transportation System management (TSM): involves all aspects of traffic engineering in a focus on

optimizing system capacity and operations. Specific aspects of TSM include high-occupancy vehicle

priority systems, car-pooling programs, pricing strategies to manage demand and similar functions.

Integration of Intelligent transportation system technologies (ITS): refers to the application of modern

telecommunications technology to the operation and control of transportation systems. It includes

automated highways, automated toll-collection systems, Vehicle tracking systems, in vehicle GPS and

mapping systems, automated enforcement of traffic lights and speed laws and smart control devices.

1.2 Objectives and scope of Traffic Engineering

The basic object of traffic engineering is to achieve efficient free and rapid flow of traffic with least

number of traffic accidents. The definition of traffic engineering highlights the following objectives:

• Safety

• Speed

• Comfort

• Convenience

• Economy

• Environmental Compatibility

The principal goal of the traffic engineer remains the provision of a safe system for highway traffic.

Other objectives are self-evident desires of the traveler. Everyone wants their trip to be fast,

comfortable, convenient, cheap and in harmony with the environment. All of these objectives are also

relative and must be balanced against each other and against the primary objective of safety.

Safety: The specular increase in the number of motor vehicles on the road has created a major social

problem- the loss of live through accidents. The appalling human misery and the serious economic loss

caused by the road accidents demand the attention of the society and call for the solution of the problem.

The traffic engineer plays a major role here since many features of the highway affect the safety of the

vehicle and the other road users. The analysis of the accident statistics provides clues to the many factors

that lead to the accident and to improvements that may be desired. Based on the statistics the traffic

engineer must device ways to reduce the accidents through better planning, design, construction

maintenance and traffic operation. The traffic engineer is also concerned about the regulation and

management of traffic to ensure safer travel. Accident data supply valuable information to control,

regulate and manage the traffic more effectively.

Speed: Speed of travel is much to be desired, is limited by transportation technology, human

characteristics, and the need to provide safety.

Comfort and Convenience: comfort and convenience are generic terms and mean different things to

different people. Comfort involves the physical characteristics of vehicles and roadways and is

influenced by our perception of safety. Convenience relates more to the ease with which trips are made

and the ability of transport systems to accommodate all of our travel needs at appropriate times.

Economy: economy is also relative. There is little in modern transportation systems that can be termed

“cheap”. Highway and other transportation systems involve massive construction, maintenance and

operating expenditures, most of which are provided through general and user taxes and fees. Every

engineer, regardless of the discipline, is called upon to provide the best possible systems for the money.

Environmental Compatibility: Harmony with the environment is a complex issue that has become more

important over time. All transportation systems have some negative impact on the environment. In many

modern cities, transportation systems utilize as much as 25% of the total land area. “Harmony” is

achieved when transportation systems are designed to minimize negative environmental impacts, and

where system architecture provides for aesthetically pleasing facilities that “fit in” with their

surroundings.

1.3 Role of Traffic Engineer

The traffic engineer has a very special relationship with the public at large. Perhaps more than any other

type of engineer, the traffic engineer deals with the daily safety of a large segment of the public. The

functions of a traffic engineer include the following:

• Collection, analysis and interpretation of data pertaining to traffic

• Traffic and transportation planning

• Traffic design

• Measures for operation of traffic

• Administration

Collection, analysis and interpretation of data pertaining to traffic: One of the important functions of a

traffic engineer is to organize and implement various traffic surveys and to collect data pertaining to

traffic characteristics. Volume counts, speed, travel time and delay measurements; accident and parking

characteristics are some of such studies. The data collected by such studies are analyzed by the traffic

engineer and interpreted to take advantage of the observed regularities. An accurate understanding of the

data will help the traffic engineer to select appropriate solutions to problems.

Traffic and Transportation planning: Traffic engineer is concerned with preparation of traffic and

transportation plans to ensure a safe, orderly and fully integrated transportation system. This phase of

activity concerns itself with the relation of land use with transportation and study of travel

characteristics. Based on the analysis of the results of such a study, mathematical models are formulated

to predict how a system will behave under a given set of conditions. Alternative solutions are formulated

and analyzed and finally an optimal solution is selected.

Traffic Design: This part of traffic engineer includes the geometric design of highways and streets,

intersection designs, design of off-street and on-street parking facilities, deign of bus and truck terminal

services, design of traffic control devices such as signal timing and traffic signals and other traffic

facilities. The traffic engineer also has a responsibility to protect the community from liability by good

practice. This includes

• Placing control devices that do not conform to applicable standards for their physical design and

placement.

• Failure to maintain devices in a manner that ensures their effectiveness.

• Failure to apply the most current standards and guidelines in making decisions on traffic control,

developing a facility or a design plan.

• Implementing traffic regulation.

Measures of operation of traffic: for efficient and safe operation of traffic, the traffic engineer has to

take recourse to a number of measures such as

• Legislation and enforcement measures for regulation of road users (drivers, pedestrians,

passengers, vehicles)

• Management measures such as one-way streets, prohibited turnings at junctions and tidal flow

measurements, exclusive bus lane etc. with a view to get the maximum out of the available street

facilities.

• Measures of regulation on parking vehicles.

• Control measures such as traffic signs, signals, road markings and channelization techniques to

guide and secure the safe and efficient flow of traffic.

Administration: The traffic engineer also functions in a world in which a number of key participants do

not understand the traffic and transport issues. This include elected and appointed officials with

decision-making power, the general public and other professionals with whom traffic engineers work on

an overall project team work. The traffic engineer has to organize and administer the various

programmes intended to secure safe and efficient traffic in towns and cities.

Assignment:

Each student must submit an INDIVIDUAL response to this assignment. Be sure to indicate your name

on the first page of your "report." Mail the report to: reashmaps@revainstitution.org

1. Discuss the importance or need of Traffic Engineering under Indian Conditions. [Refer the

papers attached with this].

2. Mention some of the traffic engineering organizations in India. Also describe the traffic

engineering administration in a department.

3. List out five national and international journals in traffic engineering discipline. List out ten

papers in traffic related area according to their average citation index.

References:

1. William R McShane, Roger P Roesss, and Elena S Prassas. Traffic Engineering. Prentice-Hall,

Inc, Upper Saddle River, New Jesery, 1998.

2. L. R Kadiyali. Traffic Engineering and Transportation Planning. Khanna Publishers, New Delhi,

1987.