VI. RESEARCH WORK DONE IN ACADEMIC INSTITUTIONS RELATED TO THESIS WORK

D. TRAFFIC AND TRANSPORTATION
2. Study of the Impact of Introducing Stop-Control at Uncontrolled Intersections Using Computer Simulation
Date of Start

August 2005
Indian Institute of Technology Madras (R, C)

 

Scope and Objectives

The conflicts and delay experienced by vehicles, is probably the most desirable criteria, based on which, the performance of uncontrolled intersections can be evaluated. Collection of data on these aspects involves close observation of individual vehicles passing through the intersection from a point on the approach, where the influence of the intersection does not exist, to a point beyond the exit of the intersection where the influence of intersection has totally dissipated. Collection of such data is extremely difficult; and time consuming. However, the availability of high-speed computers has facilitated the use of powerful techniques, such as calibrated simulation models with field observed data to study the traffic characteristics, including conflicts and delay. By computer simulation, the traffic flow through intersections can be precisely modeled; closely representing the field conditions, and the conflicts and delay caused to individual vehicles can be obtained as the output components of the simulation process. In this study, an attempt has been made to simulate the traffic flow at urban uncontrolled intersections under heterogeneous traffic environment in order to estimate the conflicts and delay caused to vehicles under various traffic flow situations and introducing stop-control at this uncontrolled intersection to reduce conflicts. The objectives of the study are as follows:

• To study the mixed traffic flow characteristics at uncontrolled intersections through field observations.

• To study the level of accident risk interms of traffic conflicts, at uncontrolled intersections for various traffic flow levels and composition by making use of the available simulation model.

• To modify the available model to simulate traffic flow through stop controlled intersections.

• To study the reduction in the level of accident risk due to the introduction of stop control system using simulation technique.

• To develop appropriate guidelines for introducing stop control under mixed traffic conditions prevailing in India.

 
Findings and Conclusions
(i) The comparison of overall delay caused to vehicles at uncontrolled and stop controlled intersections for the three roadway conditions with variation of traffic volume, reveals that for a given roadway and traffic conditions, the overall average delay caused to traffic is more in the case of stop controlled intersections than in the case of uncontrolled intersections.

(ii) The comparison of intersection-area stopped delay caused to vehicles at uncontrolled and stop controlled intersections for the three roadway conditions with variation of traffic volume, reveals that for a given roadway and traffic conditions, the intersection-area stopped delay caused to traffic is less in the case of stop controlled intersections than in the case of uncontrolled intersections.

(iii) The comparison of the level of accident risk, measured in terms of crossing conflicts, to vehicles at uncontrolled and stop controlled intersections for the three roadway conditions with variation of traffic volume, reveals that for a given roadway and traffic conditions, the level of accident risk to traffic is less in the case of stop controlled intersections than in the case of uncontrolled intersections.

(iv) It is found that the overall average delay is more or less the same in the cases of both the uncontrolled and stop controlled intersections up to a volume level of 400 vehicles per hour.

(v) The number of crossing conflicts are approximately the same up to the volume level of 400 vehicles per hour in the cases of both uncontrolled and stop controlled intersections.

(vi) The average overall delay increases steeply, in the cases of both uncontrolled and stop controlled intersections, beyond the volume levels of 900, 1000 and 1100 vehicles per hour respectively in the cases with 3.75 m, 5.0 m and 7.5 m wide approach roads.