Traffic flow analysis of digital count down signalized urban intersection

Intersections are bottleneck in the urban highway network and critical determinant of system's capacity, efficiency and safety. Recently, several countdown timers had been installed at intersections in Kuala Lumpur and some other cities in Malaysia. The function of these timers is to aid drivers to judge the amount of time left for them to get the green signal for starting their vehicles. This advance information is supposed to help drivers in reducing their initial delay especially for the first few vehicles. In the present research one intersection in a non-CBD area has been analyzed to study the effect of count down timer on driver behavior and intersection approach capacity. The data is collected at the same intersection before and after the installation of count down signal in order to exclusively study the effect of timer, keeping other factors the same. The intersection approach capacity of countdown signal is compared with normal signal and other standards. The study suggests that countdown timer has got very little effect on capacity. Though there is large variation in capacity values for different cycles, but the average capacity values for both countdown and normal signal approach are very close to US Highway Capacity Manual values. For the safety level comparison of conventional and timer signalized intersections the data for red light running is analyzed and results are reported.