Using ACC Vehicles to Control Traffic Flow on Semi-Autonomous Highways

Project summary:

Vehicles equipped with Adaptive Cruise Control (ACC) feature will become widely available in the near future. ACC enhances the current cruise control capabilities by being able to monitor and control headway distances as well as the vehicle speeds. The original tenet for the development of ACC is to add safety and comfort features and previous research has focused mainly on these issues. However, the use of ACC vehicles to improve traffic flow, in addition to enhancing drivers' comfort and safety have not been investigated. We propose that if ACC driving behaviors (i.e. the relationships between vehicle speeds and inter vehicle distances) are appropriately assigned, ACC vehicles may in aggregate have positive impact on the throughputs and the level of service provided on the highway system. ACC vehicles in essence become moving traffic control devices on the highway with mixed (manually driven and ACC vehicles) traffic. They have the potential of directly influencing the traffic dynamics through appropriately assigned driving behaviors; and thus may be effective in clearing already congested highways, or in organizing traffic before bottleneck regions like work zones. They may also allow the theoretical capacity of the highway to be more fully utilized by organizing traffic to flow in a desirable manner. The objectives of the present research are to investigate the feasibility and benefits of using ACC to improve traffic flow on highways with mixed ACC and manual vehicles, and to identify the type and content of the information (if any) that needs to be relayed to the ACC vehicles.