Research on Safety Level of Service at Urban Tunnel Convergence Section

We propose a method of using safety level of service to evaluate the traffic safety of convergence sections between the entrances and exits of two urban tunnels. The conflict probability index is established by the conflict circle method. Time to crash (TTC) is treated as an index for measuring the severity of conflict. The probability of crash is established by integrating the conflict probability and conflict severity. The collision severity index is established according to the kinetic energy conversion relationship. Finally, the overall safety evaluation model of the road section is established. The safety index threshold is determined and the safety level of service is classified using an engineering example. This provides the theoretical guidance for traffic safety evaluation and improvement of the urban tunnel convergence section in the last section.