Design Consistency Evaluation Methods for Freeway Long Tunnels in China

Compared to traffic accidents on sections of open road, the consequences of traffic accidents are worse in a tunnel, especially for a long tunnel. In order to improve the safety performance of long tunnels in China, the effects of geometric alignments of long tunnel entrance on average speed and speed difference for passenger vehicles and trucks, as well as the heart rate increment of drivers, are analyzed using statistical analysis and regression method. The research results show that the effects of geometric alignments on average speed and speed difference at the tunnel entrance section for passenger vehicles is relatively small and the effect on average speed and speed difference for trucks is relatively large. The combined influence of the horizontal and vertical alignment of tunnel entrance on heart rate increment of drivers is deterministic. Based on research findings on the speed difference of vehicles and heart rate increment of drivers, consistency evaluation methods and corresponding evaluation criteria for long tunnel entrance section are proposed. These methods are helpful in optimizing geometric design of long tunnel entrance sections.