Eco-driving of connected autonomous vehicles in urban traffic networks of mixed autonomy with cut-in and escape lane-changes of manually-driven vehicles

Urban eco-driving of connected autonomous vehicles (CAVs) aims to optimize CAVs' speed trajectories to avoid sharp accelerations/decelerations and stops at signalized intersections for the minimization of energy consumption of mixed traffic of CAVs and manually-driven vehicles (MVs). Existing eco-driving studies rarely considered lane changes of MVs. Besides ordinary lane changes that usually take place in traffic flow, eco-driving CAVs tend to trigger specific types of lane changes of MVs, i.e. cut-in from adjacent lanes to the front of CAVs, or escape from behind CAVs to adjacent lanes. It is significant to investigate the interplay between such extraordinary lane changes of MVs and eco-driving endeavors. This paper has developed a generic and deployable eco-driving strategy for CAVs that can deal with both lateral disturbances (e.g. cut-in and escape lane changes of MVs) and longitudinal disturbances (e.g. MVs moving in front and vehicle queues at downstream intersections), without assuming communications between CAVs and MVs. The eco-driving task was formulated as an optimal control problem with safety constraints, and tackled under a unified rolling-horizon framework, with each cut-in lane change treated as a newly emerging longitudinal disturbance to CAVs. The eco-driving performance was thoroughly evaluated for an urban multilane road network based on SUMO. The eco-driving strategy was demonstrated capable of tackling various disturbances of MVs and effectively achieving the eco-driving purpose. For the eco-driving effects on lane changes of MVs, the numbers of cut-in and escape lane changes ascended until the market penetration rate (MPR) of CAVs reached 30% and then kept decreasing, while the number of ordinary lane changes dropped monotonically with the MPR increase. As to the impact of cut-in and escape lane changes of MVs on eco-driving, the energy saving benefits of all CAVs and MVs grew with the MPR increase, despite the disturbances of MV lane changes. Similar results were not reported before.