A Statistical Approach to Estimate Severe Accident Vehicle Collision Probability Inside a Multi-lane Road Tunnel with Unidirectional Traffic Flow

Dynamic risk estimation of the tunnel is an important aspect of tunnel safety. Severe accident collision probability is an important parameter in the dynamic tunnel risk assessment process as it is needed to build a probabilistic dynamic risk model of a tunnel. This helps in continuous monitoring of the risk of the tunnel from severe accidents and can enable tunnel management to take appropriate control measures to restrict the risk when it crosses a certain threshold. This paper tries to estimate the severe accident probability of collision when a vehicle enters a lane of a tunnel at a certain speed. The three-lane Bhatan tunnel on Mumbai-Pune Expressway in India was considered for the analysis and modeling of the traffic flow. A traffic simulation of one year is performed with 13 million vehicles to come out with the number of overtaking that can happen with a given speed of a vehicle. An exponential regression model was used to predict the number of overtaking. A suitable Weibull distribution was used to predict the severe accident collision probability using the number of overtaking.