Range policy of adaptive cruise control for improved flow stability and string stability

This paper presents the problem of designing a range policy for adaptive cruise control systems and a companion control algorithm for improved traffic flow stability and string stability. A nonlinear range policy is proposed and its performance is compared against a constant time-headway policy and the range policy employed by human drivers, with special attention on traffic flow stability. The proposed range policy is obtained from the solution of an optimization problem under traffic flow requirements. A sliding mode controller is then designed to work with the range policy. Simulation results show that higher and sustainable (stable) traffic flow is achieved by the proposed method.