An Infrastructure Assisted Concept for Automated Highway Systems

An Automated Highway System (AHS) is defined as a vehicle-freeway system that enables hands-off feet-off driving on dedicated lanes. This paper documents an AHS concept, developed by the National AHS Consortium as one of five promising concepts. The concept features vehicle-to-vehicle communication, communication and distributed intelligence between the vehicle and the infrastructure. The concept is tailored to support two different vehicle-following rules, i.e., free-agent and platooning. Vehicle-to-vehicle communication enables higher throughput via smaller average longitudinal spacing and higher safety through vehicles' mutual informing of status and intent and through maneuver coordination for normal maneuvers and abnormal events, including failures and collisions. Infrastructure-to-vehicle communication is on a broadcast basis. This communication enables operational intelligence to be distributed between the vehicle and the infrastructure, which in turn enables maximization of throughput and safety while minimizing the overall vehicle system cost. Physical isolation of automated traffic provides uniformity of vehicle automation capability, which increases safety and throughput and reduces the technological sophistication and hence the cost.