Abstract:
Capacity of signalized intersections is the key parameter in operating and performing traffic in urban roadways network. Recently, several countdown timer traffic signals have been installed at intersections in many Egyptian cities. The main function of these timers is to provide drivers with the remaining time of the current indicator (e.g. red and green) until the onset of the next interval time. This paper reports a before and after study which evaluates the difference in driver response along an approach of a signalized intersection installed with a traffic signal countdown device. Accordingly, two main objectives are stated for this study the first one is to investigate the effect of the red indicator countdown device on start-up delay time of queued vehicles, the second objective is to investigate the effect of the green indicator countdown device on the number of drivers who violate the red time. The required data for this study was collected at an approach of a signalized intersection in Shebin El-Kom city by using video recording technique. The data was collected before and after installing the countdown device at this intersection using video tap recording. The findings provided an answer for the question of that to what extent do the countdown timer devices improve the response of the driver at traffic signals? It was found that the countdown traffic signals significantly affect the driver's behavior and reduce the start-up delay. The findings also indicated that there was no significance difference in the number of red-running violations after the installation of the countdown timers.