Critical Driving Speed Research on Tunnel Group Connection Segments

Considering the traffic safety in a tunnel group, the tunnel group was defined. The formula of critical driving speed in free drive status and car-following status was given according to the safe driving distance model. According to the model, the factors of the tunnel group, such as the coefficient of friction, the speed, the reaction time were analyzed and valued under different weathers and different road surfaces. Then, the critical driving speeds were given in different conditions. The result shows that the critical driving speeds can provide a basis for the safety management in the tunnel group.