How do accidents happen: a deadline-type experiment on maintaining safety margins

The results of 5 subjects in a deadline-type laboratory task, simulating a hazardous activity with a trade-off between safety and efficiency, showed two basic categories of accident potential. The first one stems from the very normal behavior in which the subjects maintain too small margins of safety and incur an accident in the case of certain coincidences. The second is based on major errors in decision-making or performance resulting in deviant behavior which either is a sufficient cause of an accident or much increases the probability of an accident when the system does not provide sufficient margins of safety.