Analysis of Cooperative Driving Strategies for Nonsignalized Intersections

In this paper, we study the difference between two major strategies of cooperative driving at nonsignalized intersections: namely the "ad hoc negotiation-based" strategy and the "planning-based" strategy. The fundamental divide of these two strategies lies in how to determine the passing order of vehicles at intersections. The "ad hoc negotiation-based" strategy makes vehicles roughly follow first-come-first-served order but allows some adjustments. This leads to a local optimal solution in many situations. The "planning-based" strategy aims to find a global optimal passing order of vehicles. However, constrained by the planning complexity and time requirement, we often stop at a local optimal solution, too. We carry out a series of simulations to compare the solutions found by two strategies, under different traffic scenarios. Results indicate the performance of a strategy mainly depends on the passing order of vehicles that it finds. Although there exist several trajectory planning algorithms associating with the solving process of passing orders, their differences are negligible. Moreover, if the traffic demand is very low, the performance difference between two strategies is small. When the traffic demand becomes high, the "planning-based" strategy yields significantly better performance since it finds better passing orders. These findings are important to cooperative driving study.