A Motor Vehicle Accident Causal System: The Human Element

A motor vehicle accident causal system, from a human factors viewpoint, is presented. The system, or model, is based upon a cause and effect relationship: the“effect”being the primary failure or behavior which led directly to the collision situation; the“cause”being the reasons for the failure or behavior. Effects are described as information-processing failures of four types: (1) perception, (2) comprehension, (3) decision, and (4) action failures. The reasons for these information processing failures are categorized as (1) physical or physiological failures, (2) driver conditons or states, (3) experience or exposure factors, (4) conflicting behaviors or preoccupation, and (5) risk-taking behaviors. A causal reporting system for utilization by accident research groups is discussed in terms of primary or principal causes, severity–increasing factors, and relevant conditions. Two recent studies which used similar causal systems are described and findings from them are presented. A discussion of the possible benefits of such a system as results emerge is related to driver education and training techniques.