Traffic and Safety Implication of Adaptive Cruise Control for Two- lane Two-way Highways Traffic Operation

Potential impacts of Adaptive Cruise Control (ACC) system on safety and traffic operation of two-lane two-way highways have not been adequately researched. This mainly regards to how ACC influences overtaking maneuver when vehicle are equipped with an activate ACC. ACC is intended to keep safe headways between vehicles in the traffic stream; however, this can also affect overtaking decision and the passing process due to larger initial headways between overtaking and overtaken vehicles at the beginning of the maneuver. In this paper, microscopic simulation model is used to investigate the potential impacts of ACC system on overtaking maneuvers for two-lane highways and its resultant safety and traffic effects. Traffic and safety measures including average travel speed, percent time spent following, number of overtakes, overtaking time, and times to collision to the oncoming vehicles are measured for different ACC scenarios as well as for normal following condition where no ACC is in effect. The results showed that ACC can significantly impact safety and traffic indices associated with overtaking maneuver on two-lane two-way highways.