Identifying and explaining the reducing risk factors and the factors influencing safety in road tunnels

Growth of various industries particularly transportation industry on the one hand increases the level of public welfare and on the other hand reduces the level of safety incidents. Certainly in line with the progress of different industries, safety level should also be increased. Transportation industry is divided into several categories that road transport is one of them, among them on of the most important parts of the road passages, are tunnels. Tunnels are of such technical buildings of the ways that using them has many advantages, including reducing travel time, reducing fuel consumption, reducing environmental pollution, but functionality and performance of tunnels is severely affected by safety systems. Events mostly occurred in the tunnel because of its special structure have more serious outcomes than other places along the road. Therefore how to build secure tunnels and how to maintain it is essential. In this study, we identify the risks affecting the safety of road tunnels and then divided them into three categories: basic agents, intermediaries and mother.