Towards a Congruent Interpretation of Traffic Rules for Automated Driving - Experiences and Challenges

Kurzfassung

The homologation of automated driving systems for public roads requires a rigorous safety case. Regulations of the United Nations demand to demonstrate the compliance of the developed system with local traffic rules. Hence, evidences for this have to be delivered by means of formal proofs, online monitoring, and other verification techniques in the safety case. In order for such methods to be applicable traffic rules have to be made machine-interpretable. However, that pursuit is highly challenging. This work reports on our practical experiences regarding the formalization of a non-trivial part of the German road traffic act. We identify a central issue when formalizing traffic rules within a development process, coined as the congruence problem, which is concerned with the semantic equality of the legal and system interpretation of traffic rules. As our main contribution, we delineate potential challenges arising from the congruence problem, hence impeding a congruent yet formal interpretation of traffic rules. Finally, we aim to initiate discussions by highlighting steps to partially address these challenges.