Abstract:Autonomous vehicles play an important role in easing traffic congestion and eliminating traffic accidents. In order to ensure the safety and reliability of the autonomous vehicle, there must be an all-around test before they are deployed on public roads. Most of the existing test scenario data come from traffic accidents and traffic violations. Furthermore, the most fundamental safety requirement of an autopilot system is that autonomous vehicles should comply with traffic law, which fully reflects the importance of autonomous vehicles complying with traffic rules. Nevertheless, there is a severe lack of test scenarios built for the traffic law. Therefore, in this study, the safety requirements of the autopilot system are extracted from the traffic law perspective, and a Petri net modeling and formal verification method for intersection test scenarios is proposed. Firstly, the traffic rules are classified according to the test scenarios of automated driving, the rule text suitable for the autonomous vehicle is extracted and semi-formalized. Secondly, with the aim of covering traffic law and function testing procedure of the test scenario, the interactive behavior of the intersection scene elements is integrated, the typical test scene elements are selected and combined to deploy the intersection test scenarios. Then, the test scenario based on traffic rules is modeled as a Petri net, in which places describe the state of the autonomous vehicle and transitions represent the trigger condition of the state. Moreover, the Clock Constraint Specification Language (CCSL) is chosen as the intermediate semantic language to convert the Petri net into an intermediate semantic model which can be formally verified. A specific conversion method is proposed. Finally, Tina is used to verify the activity, boundedness, and accessibility of the traffic-law scenario model, and the experimental results prove the validity of the model. Besides, the CCSL constraints are analyzed through the analysis tool MyCCSL which is based on the SMT and the consistency of the model is verified by the LTL formula.