Formalizing traffic rules for uncontrolled intersections

One of the challenges in designing autonomous vehicles (AV’s) is driving around humans (i.e. drivers, cyclists, pedestrians, etc.) In particular, the AV’s and the humans must have a common set of traffic rules to follow. In this paper, we present a new approach to formalize and implement traffic rules. We use California’s DMV driver handbook as a working example. Our approach provides a straightforward mapping from the rules in the handbook to its formal model, and from the model to its implementation. To demonstrate the efficiency of this approach, we formally model the traffic rules in the logic programming paradigm of Answer Set Programming (ASP) using a programming language called Clingo. We then integrate these rules into CARLA, a virtual test bed environment for autonomous vehicles. We simulate the behavior of autonomous vehicles at four way and three way uncontrolled intersections by correct reasoning of right-of-way rules for autonomous vehicles in real time. As a result, the behaviors of autonomous vehicles under our controller are more realistic compared to CARLA’s default FIFO controller. This also improves the throughput of the traffic through the intersection.