A Performance Analysis of Mixed Platoon Control under Communication Delay

Based on technologies of automatic control and wireless communication, e.g., vehicle-to-vehicle(V2V)communication, intelligent and connected vehicles(ICVs)are believed to improve traffic performance significantly. This paper investigates the performance of mixed platoon systems consisting of ICVs, adopting cooperative adaptive cruise control(CACC), and human-driven vehicles(HDVs)under the influences of communication delay in vehicular networks. From microscopic car-following behaviors, the minimum time headway for string stability is obtained based on the frequency-domain transfer function and increases as time delay grows up, verified by numerical calculation. Large-scale traffic simulations under multiple penetration rates are conducted from traffic shockwaves, with three cases under consideration, including CACC without delay, CACC with delay, and adaptive cruise control(ACC), which degrades from CACC at an extensively considerable delay. Given the same headway for the three cases, extensive simulation results show that CACC without delay or with a communication delay of 1 s can reduce traffic perturbations and dampen traffic shockwaves, with no evident performance gaps. By contrast, ACC achieves a much worse performance compared to CACC.