Exploring factors affecting injury severity of crashes in freeway tunnels

Identifying and understanding factors which affect crash injury severity is critical for developing plans to ensure traffic safety in freeway tunnels. Potential factors, such as traffic volume, tunnel environment, geometric design, and weather were considered to predict the likelihood of injury severity. A generalized ordered logit model is developed by using police-reported crash records of selected freeway tunnels in China. The results indicate that five factors are significantly related to injury severity, which include Season, Time of Day, Location of Crash, Tunnel Length, and Adverse Weather. The summer season seems discouraging the probability of sustaining fatal injuries. The likelihood of no injury crashes seems to increase during night-time. Crashes occurred near tunnel entrance/exit tend to be more severe than those occurred inside the tunnels. Tunnel length and weather were also found positively affecting the likelihood of injury severity.