Towards provably safe mixed transportation systems with human-driven and automated vehicles

Currently we are in an environment where the fraction of automated vehicles is negligibly small. We anticipate that this fraction will increase in the coming decades before, if ever, we have a fully automated transportation system. Motivated by this we address the problem of provable safety of mixed traffic consisting of both intelligent vehicles (IVs) as well as human driven vehicles (HVs). An important issue that arises is that such mixed systems may well have lesser throughput than all-human traffic systems, if the automated vehicles are expected to remain provably safe with respect to human traffic. This necessitates the consideration of strategies such as platooning of automated vehicles in order to increase the throughput. In this paper we address the design of provably safe systems consisting of a mix of automated and human-driven vehicles including the use of platooning by automated vehicles. We design motion planning policies and coordination rules for participants in this novel mixed system. HVs are considered as nearsighted and modeled with relatively loose constraints, while IVs are considered as capable of following much tighter constraints. HVs are expected to follow reasonable and simple rules. IVs are designed to move under a model predictive control (MPC) based motion plans and coordination protocols. Our contribution in this paper is in showing how to integrate these two types of models safely into a mixed system. System safety is proved in single lane scenarios, as well as in multi-lane situations allowing lane changes.