A real-time collision risk assessment method at tunnel entrance based on safety field theory

The main aim of this study was to propose a comprehensive risk indicator to identify the potential driving risk caused by the changing environment at tunnel entrance. Driving decisions are affected by many external factors, especially at the entrance of tunnels. However, driving indicators are mostly considering vehicle movement status currently. In this study, a safe potential field model including obstacle potential field, vehicle potential field and lighting potential field is constructed to evaluate influence of roads, drivers, vehicles, and change lighting conditions on driving risk. Furthermore, considering the driving risk distribution and its temporal change rate, a comprehensive driving risk indicator (CDRI) was established to evaluate the magnitude of driving risk. Finally, the comparison between CDRI and the other two classic risk indicators indicates that the CDRI proposed in this paper has a better performance in the safety assessment at tunnel entrance. It is expected that the finding in this study could be valuable in developing control and measures for in-tunnel driving risk declining.