Safety modeling and evaluation of Automated Highway Systems

This paper addresses safety modeling and evaluation of automated highway systems, based on the use of platoons of vehicles driven by automated agents. We analyze the impact on safety of the strategy used to coordinate the vehicles' operations, inside each platoon and between platoons, when vehicles enter or exit the highway, or when maneuvers are carried out to recover from failures affecting the vehicles or their communication. To cope with the complexity of the studied system, a compositional approach based on stochastic activity networks is developed. Replicated submodels associated with each vehicle, describing the corresponding failure modes and recovery maneuvers and their severity, are composed with submodels characterizing the configuration of the platoons and their dynamic evolution. Numerical results are presented to highlight the impact of the coordination strategy and other dependability related parameters.