Impacts of Cooperative Adaptive Cruise Control on Freeway Traffic Flow

TLDR

This study is the first to evaluate ACC and CACC effects on traffic using real driver time‑gap data from a field experiment. Microscopic simulation modeled highway capacity under different market penetration levels of ACC and CACC vehicles. ACC had little impact on lane capacity, whereas CACC substantially increased capacity at moderate to high penetration, and this effect could be further enhanced by equipping non‑ACC vehicles with vehicle‑awareness devices to act as lead vehicles.

Abstract

This study used microscopic simulation to estimate the effect on highway capacity of varying market penetrations of vehicles with adaptive cruise control (ACC) and cooperative adaptive cruise control (CACC). Because the simulation used the distribution of time gap settings that drivers from the general public used in a real field experiment, this study was the first on the effects of ACC and CACC on traffic to be based on real data on driver usage of these types of controls. The results showed that the use of ACC was unlikely to change lane capacity significantly. However, CACC was able to increase capacity greatly after its market penetration reached moderate to high percentages. The capacity increase could be accelerated by equipping non-ACC vehicles with vehicle awareness devices so that they could serve as the lead vehicles for CACC vehicles.