Hierarchical control of mixed traffic flow for mobility and energy economy promotion at signalized intersection

The emergence of vehicle-to-infrastructure and vehicle-to-vehicle wireless communication offers alternative perspectives to improve traffic mobility in urban road traffic network, but most of the existing research mainly focuses on fully automated scenarios or assume that all vehicles have communication capabilities. To compensate the research shortcomings, this paper considers a mixed traffic flow consisting of various vehicles with different levels of intelligence, and proposes a hierarchical optimal control strategy for isolated signalized intersections in rural roads to maximize traffic mobility and vehicle energy efficiency by controlling only a few connected autonomous vehicles (CAVs). In the upper layer, the mixed traffic flow near the intersection is dynamically divided into multiple “1+m” mixed platoons composed of one leading CAV and m following vehicles. In the lower layer, an optimal control framework for the mixed platoon system is established to optimize the velocity trajectory of the leading CAV, with the goal of enhancing energy efficiency, driving comfort and traffic mobility of the entire platoon. The simulation results demonstrate that the proposed strategy is suitable for any random mixed traffic scenarios and provides significant benefits in terms of traffic mobility and energy efficiency in almost all scenarios.