Alleviation of traffic congestion using distributed autonomous control in mixed traffic flow of vehicles with adaptive cruise control and human-driven vehicles

Abstract

The number of vehicles equipped with adaptive cruise control (ACC) is increasing, reflecting a trend toward autonomous vehicle development. It is expected that ACC systems will improve traffic in terms of string stability (i.e., attenuation of spacing errors along a vehicle string). For a group of vehicles without string stability, fluctuation in inter-vehicle distance is amplified as it propagates rearward, which may cause traffic congestion. It will take a few decades to replace all human-driven vehicles with autonomous vehicles. Communication technology such as fifth-generation mobile communication systems enables vehicle-to-vehicle communication with a sufficiently small delay. This paper proposes a method for avoiding traffic congestion based on distributed autonomous control. In the proposed method, autonomously controlled vehicles that satisfy string stability are distributed with adequate spacing to constrain the fluctuation of the distance between human-driven and standard ACC vehicles. The conditions for the string stability of distributed autonomously controlled vehicles are derived. The validity of the proposed method is demonstrated using numerical simulations.

Keywords

• traffic congestion
• adaptive cruise control
• string stability
• mixed traffic flow
• human-driven vehicle