Building on a Traffic Code Violating Monitor for Autonomous Vehicles: Trio Overtaking Model

Abstract

The present study aims at filling the gap between the existing traffic regulation and the technical specification for construction or behavior in operation of autonomous vehicles. The former is provided in generic and often complicated texts as the lawyers tend to cover with a single formulation all possible cases, including those not yet identified. On the contrary, for the latter, the engineers need to identify any possible situation in advance and produce precise instructions to assess, approach and deal with it, to be embedded in the safety and security logic of the self-driving vehicle.

The author builds on his previous work regarding the formalization of traffic code from the natural language to computer language, in a three steps methodology including Legal, Logic and Engineering Analyses. The previous development on Logic Analysis was extended with the multi-level hierarchy of predicates and their interpretation for Perform-Overtaking phase and with their associated Linear Temporal Logic (LTL) Formulas. This codification prepared the ground for the Engineering Analysis where the Trio Overtaking Model (TOM) was developed, considering the influence of the forerunner car over the dynamics of Overtaking (Autonomous) and of overtaken vehicle. As a premiere for three vehicle case, 25 combined scenarios were defined as matrix and for their analysis, the formal definitions, theorems, Collision Matrix and the Safe Distance Matrix were introduced. Applications for runtime checking and monitoring, synchronous (runtime enforcement) and asynchronous (e.g. black box analyze) within a Traffic Code Violating Monitor, were proposed.