FINAL YEAR PROJECT PRESENTATIONLAFINHAN OLUWATOBI OLANIYI149666

SUPERVISOR: Dr. F. O. AKINTAYO

JANUARY, 2015.

PROJECT TITLE

DESIGN OF A PRE-TIMED TRAFFIC SIGNAL

AT THE UNIVERSITY OF IBADAN MAIN GATE

BACKGROUND TO THE STUDY(Congestion as a global problem)•Urban Traffic Congestion is a significant and

growing problem in many parts of the world.(EASTS, 2001)

•The conventional approach of building more roads can no longer be the panacea.

•Traffic control techniques and information systems are needed to substantially increase capacity and improve traffic flow efficiency.

BACKGROUND contd.(Definition of Congestion)• A myriad of definitions exist for “congestion” for the

following reasons▫Operational Perspectives.▫User Perspectives.

• Joint Transport Research Centre of the OECD(Organisation for Economic Cooperation and Development) gave the following definitions▫A situation in which demand for road space exceeds supply.▫The Impedance vehicles impose on each other due to the

speed-flow relationship, in conditions where the use of a transport system approaches its capacity.

BACKGROUND contd.(Congestion in Nigeria)•The problems of traffic congestion in

urban areas seems to be worse at road intersections (Aderamo, 2012).

•At no other location within the street and highway systems were so many potential and actual conflicts, than at road intersections (Mchsare et al, 1998).

PROBLEM STATEMENT• Road traffic congestion, one of the indicators of socio-

economic vibrancy, has continually challenged the efforts of city and transport planners on highways in terms of longer travel times and delay over time and space.

• The intersection at the main entrance to the University of Ibadan currently experiences an unpleasant congestion rate and increase in delay times due to a number of factors such as:▫Increase in general population.▫Ignoring the volume of pedestrian traffic generated from

the institution.

Plate 1.1: Pedestrians crossing the UI Main Gate intersection

Plate 1.2: Near miss at the UI Main Gate intersection involving vehicles and a pedestrian

Aim and Objectives• To design a Pre-timed (Fixed Time) operated traffic

signal at the University of Ibadan Main Gate.

• Corresponding Objectives:▫To obtain traffic data.▫To undertake engineering study of current traffic

conditions, pedestrian volume, and a road inventory of the case study area.

▫To carry out analysis of the applicable factors contained in the traffic signal warrants provided in the Manual for Uniform Traffic Control Devices (MUTCD).

▫To determine the length of each signal timing phase.

Limitations •Short term traffic volume studies.

•Manual Method of counting to obtain traffic data.

•Lack of historical traffic data on case study area.

•Lack of up-to-date road network plans and profiles

Justification of study•The observations, data and results obtained from

this project provided adequate information as to designing a traffic control signal at the University of Ibadan Main Gate Intersection.

•If implemented, the traffic signal is projected to:▫Reduce congestion during peak hour flows▫Reduce potential conflicts and resulting crashes.▫Ensure safe passage of pedestrians across the

roadway.

Study Area

Plate 3.1: Satellite View of the UI Main Gate

Intersection showing the true North (Source:

Google Maps)

Plate 3.2: Aerial View of UI Main Gate Intersection

MethodologyTraffic Count

A hybrid variation of the manual method of counting was applied using a mobile application called “Traffic Abacus”

MethodologyStart Time North Approach South Approach North+

South

(Total)R S Total L S Total

Table 3.1: Recording sheet for Vehicular count collected at the Intersection

Methodology• Counts were conducted between 7.00 a.m.

and 8.00 a.m. to represent the morning peak period as well as 4.00 p.m. and 6.00 p.m. for the afternoon peak.

•Validation of the necessity of a traffic signal through Consideration of Factors in the warrants provided by the MUTCD namely:▫Peak Hour▫Pedestrian Volume

Methodology

Figure 4.2: Graphs for Peak-Hour Volume Warrant

Methodology• Saturation flow rate was determined from

field measurements following procedures outlined in the MUTCD.

•Yellow interval was calculated after which the optimum cycle length of the signal was determined using expressions from the Highway Capacity Manual (HCM) based on the concept of volume-to-capacity ratio.

Methodology•This lead to the computation of total

effective green time. The cycle length time was then validated through evaluating the minimum green time required for crossing pedestrians.

Interpretation and Discussion of Results•The volume counts at the intersection showed

the Northbound Approach (Ojoo-UI) represented 73.7% of the total volume.

•Pedestrian counts during the peak period varied between 2000 and 2400 pedestrians and showed the Westbound Approach (UI-Ojoo) comprised of 81.9% of the total volume with the percentage changing considerably during the afternoon peak period.

Interpretation and Discussion of Results

Start

Time(AM)

North Approach(Veh/15min) South Approach(Veh/15min) North+

South

(Total)R S Total L S Total

6:45 8 397 405 138 - 138 544

7:00 24 443 467 111 - 111 578

7:15 18 390 408 134 - 134 542

7:30 16 317 333 154 - 154 487

7:45 16 380 396 151 - 151 547

8:00 18 399 417 122 - 122 539

8:15 16 337 353 133 - 133 486

8:30 13 348 361 132 - 132 493

  3140 1075 4215

  75% 25% 100%Table 4.2: Vehicular Counts for Morning Peak Period (Tuesday, 21

October 2014)

Interpretation and Discussion of Results

0 15 30 45 60 75 90 105 1200

100

200

300

400

500

600

700

400418

398 395415

366

452

339

544578

542

487

547 539

486 493

MorningAfternoon

Change in Duration (Minutes)

Traff

ic V

olum

e

Figure 4.1: Graphical Representation of 15-minute Traffic volume at the Intersection (Tuesday, 21 October

2014)

Interpretation and Discussion of Results

•The peak hour was between 7.00 a.m. and 8.00 a.m. due to the hour's high consecutive 15-minute volume count corresponding to a flow of 2154 vehicles per hour.

Time Interval(AM) Total

6:45-7:00 544

7:00-7:15 578

7:15-7:30 542

7:30-7:45 487

7:45-8:00 547

8:00-8:15 539

8:15-8:30 486

8:30-8:45 493

Table 4.6: Peak Hour Volume (Tuesday, 21 October 2014)

Interpretation and Discussion of Results•The peak hour factor was computed to be

0.93, resulting in a design hourly volume of 1604 and 550 vehicles per hour for the North and South approaches respectively.

•Minimum yellow interval was computed as 3.45 seconds, with saturation flow rates of 3027 and 2156 vehicles per hour, and flow ratios of 0.57 and 0.27 for the North and South approaches respectively.

Interpretation and Discussion of Results• The total cycle length was evaluated as 110

seconds and actual green times for phase 1 and 2 were evaluated as 68 and 34 seconds respectively.

• The validation of the signal phase timings for the Intersection evaluated the minimum green time required for pedestrians crossing the critical North approach as 33 seconds which was less than the ratio of the cycle length apportioned to that phase (68 seconds), thereby passing the check.

Conclusion•A traffic study was conducted on the

University of Ibadan Main Gate Intersection and a Pre-timed (Fixed time) traffic signal was designed.

•Optimum cycle length was 110 seconds

•Total Effective Green time was 103 seconds.

Recommendations• Performing Ministries of Government concerned with

the maintenance and operation of roadways should consider installing cameras at major intersections or any other non-invasive subsurface detectors (such as magnetic or electric contact devices) to ensure availability and accuracy of vehicular count data which can be used for other important studies.

• Study of the delay at the case study intersection due to the installation of the fixed time traffic signal is needful so as to adjust the cycle length or any other appropriate parameter.

Recommendations• Further study should be embarked on to ascertain a

more effective optimum cycle length.

• Pending the possible installation of a traffic signal at the intersection, stop lines should be provided on the roadway so as to ensure the safe passage of pedestrians across the intersection.

• Sidewalks should be provided for crossing so as to avoid vehicles making a right turn into the university from being obstructed by pedestrians attempting to cross the roadway.

Contribution to Knowledge• Prior to the study, no published traffic study

was made at the intersection despite its high usage and strategic location. (The Sango-UI-Ojoo route connects two major local government areas).

• This project provides technical information about the current situation of the UI Main Gate Intersection. Information such as: Traffic Volume, Saturation Flow rate, Capacity and Flow ratios.

Contribution to Knowledge•The study represents a foundation for

future developments or improvements on the roadway.

•The study extended on research work carried out by Solomon Ayobami Adefisoye on the analysis of peak traffic flows at the main gate of the University of Ibadan. (His work provided information on the traffic inflow and outflow conditions.)

Targeted Audience•Oyo State Ministry of Works.

(Particularly the ministry involved in transportation).

•Private corporations concerned with community development projects.

•Federal Road Safety Corps (FRSC).

•NPF Controlled Nigeria Traffic Warden Service.

Plates

THANK YOU