In order to understand the relationship between tunnel vertical alignment and traffic safety, based on the statistics and analysis of accident data and road alignment data of ten expressways and their adjacent sections in Zhejiang Province for six consecutive years, the influence mechanism of the vertical alignment on the tunnel traffic safety is obtained by analyzing the vehicle speed dispersion, braking distance and accident rate of the tunnel entrance and exit sections. Finally, according to the speed prediction model, the influence mechanism of the vertical alignment of the tunnel entrance section on traffic safety is obtained. The results show that the larger the longitudinal slope in the tunnel entrance and exit area, the higher the accident rate. The accident rate is lower when the longitudinal slope of the tunnel entrance area is in the [-1.0%, 1.5%] interval and the longitudinal slope of the exit area is in the [-1.5%, 1.0%] interval; the tunnel entrance accident rate is positively correlated with the initial speed of the vehicle before entering the tunnel entrance area. The accident rate of the tunnel entrance increases with the increase of the average slope before the tunnel.

CICTP