Safety evaluation methods for long tunnels on freeways in China

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 heart rate increment of drivers were analyzed using statistical analysis and regression method in the paper. The research results show that the effects of geometric alignments on average speed and speed difference at 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 horizontal and vertical alignment of tunnel entrance on heart rate increment of drivers is deterministic. On basis of existing research findings, safety evaluation methods and evaluation criteria for long tunnel entrance section based on speed difference of vehicles and heart rate increment of drivers were provided in the paper. These methods are helpful in optimizing geometric design of long tunnel entrance section.