The Effect of Countdown Timer on the Approach Speed at Signalised Intersections

Countdown timers are being installed at major intersections of India cities without analyzing their influence on intersection safety and efficiency. This study tries to investigate the effect of green signal countdown timer (GSCT) component on the vehicular approach speeds. Two approaches of two different signalized intersections, one with countdown display and another without it, have been studied for the present study. Presence of GSCT is found to be linked with fewer red light violations (RLVs) cycles, lower number of mean RLV per RLV cycle, higher vehicular speeds during the phase transition at different locations upstream to the stop line, more number of speeding cars, and higher stop line crossing speed during amber. Overall, GSCT encourages drivers to travel with higher speed which could lead to accidents. This observation makes researchers skeptical about its real effectiveness. An additional safety based study can provide better insight about the utility of GSCT