Verified Traffic Networks: Component-based Verification of Cyber-Physical Flow Systems

We address the problem how high-fidelity verification results about the hybrid systems dynamics of cyber-physical flow systems can be provided at the scale of large (traffic) networks without prohibitive analytic cost. We propose the use of contracts for traffic flow components concisely capturing the conditions for a safe operation in the context of a traffic network. This reduces the analysis of flows in the full traffic network to simple arithmetic checks of the local compatibility of the traffic component contracts, while retaining higher-fidelity correctness guarantees of the global hybrid systems models that inherits from correct contracts of the hybrid system components. We evaluate our approach in a case study of a modular traffic network and a prototypical implementation in a model-based analysis and design tool for traffic flow networks.