A study of automatic car following

Virtually all proposed vehicle control systems for highway automation must include a steady-state car-following mode. This mode was intensively investigated for various situations where headway and relative velocity inputs were used. In addition, a fundamental relationship between the flow capacity of an automated highway and the small-signal longitudinal response of a vehicle was investigated. The predictions obtained from mathematical models of various car-following modes were compared to those from full-scale tests. It was concluded that a linear mathematical representation of the longitudinal dynamics was valid, and thus it could be used for predictive purposes. Furthermore, it was verified that flow capacity on an automated highway is sharply limited by certain vehicle characteristics if headway feedback is used for vehicle control.