Impact of Traffic Signal Countdown Displays on Driver Behaviors

Traffic signals with countdown display have been wildly used at signalized intersection. The main purpose of traffic signals with countdown display is to provide drivers with a countdown timing that would help them make informed stopping/crossing decisions during the critical phase-change period. Reflecting the human oriented principle, nevertheless, the inconsistency between traffic efficiency and safety should be taken into account. This research focuses on the driver behaviors affected by red-light countdown displays and green-light countdown displays. By means of camera data collection and data analysis, driving behavior affected by using countdown display and not using countdown display at signalized intersection was compared in this paper in a driver's view, and the safeties at signalized intersections with countdown display were analyzed. The finding indicated that the countdown display significant affected the driver's decision making, and the red-running violations was reduced with no using countdown display at signalized intersection, but the start-up delay increased. So the timing signal should be installed cautiously.