The Impact of Starting Amber Traffic Signal on Traffic Flow and Safety: a Driving Simulator Study

Abstract

Due to the growing demand for efficient transportation and limited capacity, the performance of the existing infrastructure and traffic control systems need to be optimized in order to control the growing saturation of roads and intersections. This study gives a first indication of the traffic safety and traffic flow implications of the starting amber phase on Belgian traffic signals. Non-Belgian studies reported an increased capacity of intersections after the implementation of the starting amber, but warned for an increase of early departures and violations. During the experiments of this study, forty four participants completed four experimental drives by which a comparison between the conventional traffic light scheme and the starting amber phase was made. This study concludes that a starting amber of 2 seconds has a positive impact on the traffic flow as the driver gains a time advantage of 1.1 seconds compared to the traditional traffic light scheme. Drivers could prepare themselves for the oncoming green phase and started accelerating earlier. Traffic Safety effects were tested by including conflict situations with pedestrians and crossing vehicles, but due to the usage of a driving simulator, no valid results were found. This immediately forms the foundation of further investigation.