Traffic and Safety Implication of Adaptive Cruise Control for Two-Lane Two-Way Highways Traffic Operation

Potential impacts of the Adaptive Cruise Control (ACC) system on safety and traffic operation of two-lane/two-way highways have not been adequately researched. This mainly regards how ACC influences the overtaking maneuver when vehicles are equipped with an activated ACC. ACC is intended to keep safe headways between vehicles in the traffic stream; however, this can also affect the 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, percentage of time spent following, number of overtakes, overtaking time, and time to collision with oncoming vehicle(s) - are measured for different ACC scenarios, as well as for normal following conditions 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.