An impact study of integrating connected automated vehicles with conventional traffic

Connected and automated vehicles (CAVs) promise to change the transportation landscape with safer, faster and more energy-efficient mobility. However 100% CAV penetration may never be achieved, raising the question of how to ensure a productive co-existence of CAVs with conventional vehicles. In this paper, we address the problem of optimally controlling CAVs under mixed traffic conditions where both CAVs and human-driven vehicles (non-CAVs) travel on the roads. We specifically consider problems with such mixed traffic crossing an intersection without using explicit traffic signaling, the objective being to minimize energy consumption subject to a throughput maximization requirement while guaranteeing safety constraints. The impact of CAVs on overall energy consumption is investigated under different traffic scenarios as a function of the CAV penetration rate (i.e., the fraction of CAVs relative to all vehicles). Performance under traffic light control is used as a baseline for this study. Results are validated through simulation using MATLAB and VISSIM. The results indicate that the energy efficiency improvement becomes more significant as the CAV penetration rate increases, while the significance diminishes as traffic becomes heavier.