A Causal Analysis of Large Vehicle Accidents Through Fault‐Tree Analysis

Recent trends indicate that vehicle miles traveled for large trucks is increasing at a higher rate than for other vehicles. The resulting competition between large trucks and other vehicles for highway space can be expected to result in more multivehicle collisions involving large trucks. This paper presents the result of an investigation of the causes and the mechanism related to large vehicle accidents. A fault‐tree analysis of large vehicle accidents identifies the individual roles played by driver, vehicle, and environmental factors, as well as their interactions in the accident mechanism. Using accident data for 1984‐1986, the probabilities for different basic events in the fault tree were assessed. The most likely events leading to a large vehicle accident, as well as the most effective counter measures, were then identified. The result indicate that the most prevalent form of accidents due to driver‐related failures is when a normal driver makes an error in judgment and is unsuccessful in his or her evasive action. For vehicle‐related failures, the predominant type of failure is equipment failure, and for environmental‐related failures, excessive demand on driver and vehicle performance created by the environmental or roadway factors.