How Far can We Go? Capturing Traffic Rules via Traffic Sequence Charts

The emergence of automated vehicles as active participants in traffic introduces new engineering challenges. Beyond traditional technical requirements, the engineers must now design systems that adhere to a complex set of regulations, ensuring compliance across a vast range of possible traffic scenarios. A formal specification of these scenarios is crucial-not only to facilitate communication between stakeholders during the development process but also to enable objective, tool-supported evaluation of behavioural requirements. Traffic Sequence Charts (TSCs) offer an intuitive, visual modelling language for the formal specification of traffic scenarios by representing them through sequences of images that are composed of symbols. Originally developed for the automotive domain, TSCs have been extended in recent years to cover also other transport sectors. In this paper, we demonstrate how traffic rules across the different domains-automotive, maritime, and railway-can be formally specified using TSCs as the same specification formalism. We highlight the advantages of using TSCs to capture complex regulatory requirements and discuss their strengths and limitations in general and specifically for the different domains. Finally, we outline a vision for integrating the TSC formalism into a holistic design framework for rule-compliant autonomous systems, identifying key challenges that need to be addressed and outline future work.