A configurable synchronous intersection protocol for self-driving vehicles

Road intersections represent a leading cause of traffic congestion and accidents. In fact, more than 44% of all reported crashes in the U.S. occur within intersection areas, which, in turn, lead to 8,500 fatalities and approximately 1 million injuries every year. The expected advent of self-driving vehicles raises the question of how automated and connected vehicles can be used to improve throughput at intersections while keeping them safe. A spatio-temporal intersection protocol named the Ballroom Intersection Protocol (BRIP) [5] was recently proposed in the literature to address this situation. Under this protocol, automated vehicles arrive at and go through an intersection in a cooperative fashion with no vehicle needing to stop, while maximizing the intersection throughput. Though no vehicles run into one another under ideal environments with BRIP, vehicle accidents can occur when the self-driving vehicles have location errors. In this paper, we present a safe and practical intersection protocol named the Configurable Synchronous Intersection Protocol (CSIP) that is a more general and resilient version of BRIP. CSIP utilizes a certain inter-vehicle distance to meet safety requirements against GPS inaccuracy and control failure. In addition, the inter-vehicle distances under CSIP are much more acceptable to human passengers due to longer inter-vehicle distances that do not cause fear. With CSIP, the inter-vehicle distances can also be changed at each intersection to account for different traffic volumes and GPS inaccuracies. Our simulation results show that CSIP never leads to traffic accidents even when the system has typical location errors, and that CSIP increases the traffic throughput of the intersections compared to common signalized intersections.