Exploring the heavy goods vehicle fleet behaviour through simulations: notes from the German toll system

The automatic German toll system is both a software-intensive system - relying on the on-board units to collect the toll charges due - and a socio-technical system - the user can influence the system behaviour. The overall dynamic system behaviour emerges both from the technical implementation of the system and the users´ interaction with the system limiting the effectiveness of common software engineering practices. Simulations are an additional tool to reduce the operational risks and to improve the performance of system development projects. We have developed a realistic microscopic discrete event simulation model of the automatic tolling processes to simulate the overall system behaviour at a scale of 1:1. Taking this model our research investigates the effect of the HGV fleet behaviour on the dynamic system behaviour. To that end the system simulation model is accompanied by a separate model of the HGV driving patterns.