Evaluating the Performance of Signalized Intersection with Signal Countdown Timer

Abstract

Signalized intersections are the interrupted traffic flow facility in a roadway network. The efficiency of traffic operations at the signalized intersection is expected to improve during inter-green intervals. To improve the quality of service at an intersection the traffic control devices are used widely over the world. The time intervals defined for traffic signal operation help to reduce severe traffic conflicts, delay, and improve driver’s decision for making turns. The present study evaluates the performance of traffic operations under with and without signal countdown timer (SCT) conditions based on field data collected at two signalized intersections in Hyderabad city, India. The vehicles speeding behavior and drivers complying with traffic regulation are also analyzed under different countdown timer conditions. It has been found that the average approaching speed of vehicles and red-light violations are found to be changed due to changes in the signal countdown timer conditions. The average startup loss time calculated in the field was found to be decreased when SCT was inactive. A significant increase in the capacity of signalized intersections has been observed when SCT was active. The traffic performance measures such as average control delay and queue lengths as estimated on the approaches were influenced due to the presence of STCs. The study finds that the signal countdown timer is an effective device that can enhance the traffic safety and operational performance of a signalized intersection.