Lessons learned from critical accidental fires in tunnels

Abstract

Historical data indicate that tunnel fires often cause casualties and damage to both vehicles and tunnels. These severe consequences suggest that (1) humans seldom effectively learn from history, and (2) people lack optimal safety response strategies for tunnel fires. To investigate the root causes of accidental tunnel fires and learn from them, we first surveyed the literature on historical tunnel accidents and described the common timeline of accidental tunnel fires. We employed systems thinking, based on the past research, to depict a causal loop diagram of common accidental tunnel fires. We arrived at the following three findings: (1) the literature review proved that the causes of tunnel fires are far more complex than other types of fires, and the damage they generate is greater; (2) in the context of systems thinking, accidental tunnel fires involve many causal relationships which are both continuous and dynamic, including at least three systems, namely vehicles, tunnel control, and safety response; (3) the mental models “the experience of the operators at the tunnel operation control center is just as vital as the safety response” and “safety is more critical than the traffic volume in the tunnel”, can strengthen safety response systems and ensure safe driving in tunnels. Although the structure of each tunnel and the characteristics of each fire differ and present different causal relationships, this study elucidated lessons from accidental tunnel fires and provided required messages for establishing effective safety measures. The results of this study can be used to establish systems thinking models of tunnel fires and can serve as a reference for policy planning and establishing standard operating procedures for safety responses.