Unsafe Behavior Analysis and Risk Measurement of Traffic Accidents in Mountainous Highway Tunnel

Table 2

Accident tree event description for mountain highway tunnel accidents.

Number	Meaning
	Tunnel traffic accident
	Human unsafe behaviors
	Car insecurity
	Road and environmental defects
	Security management deficiencies
	Driver-induced factors
	Passenger-related factors
	Vehicle factors
	Hazardous material transportation
	Tunnel defect
	Defects conditions
	Management defects
	Defects in emergency management
	Miss operation
	Physical and mental deficiency
	Vehicle safety hazards
	Daily check not in place
	Harsh environment
	Emergency disposal defects
	Speeding
	Overload
	Illegal overtaking
	Drowsy driving
	Drunk driving
	Sudden illness
	Psychological shadow
	Being depressed
	Weak awareness
	Affect driving
	No seat belts
	Carrying flammable and explosive articles
	On-the-road crash
	Brake failure
	Distraction
	Inadequate daily maintenance
	Poor compliance
	Poor regulation
	Complex lines
	Low road adhesion coefficient
	Design defect
	Ventilation and lighting defects
	Unclear traffic signs
	Inclement weather
	Slow emergency response
	Roadblock
	Inadequate management system
	Inadequate on-site supervision
	Insufficient safety education and training
	Inadequate emergency response system
	Lack of emergency drills
	Untimely emergency response