Visual Expert Human Factors: Accident Cause

What Causes 90% of All Automobile Accidents?

The answer is human error, primarily in perception.

There have been many studies on the causes of highway accidents. Treat (1977, et al.) performed a 5 year study that examined the causes of 2258 automobile accidents. Human error was the sole factor in 57% and a contributing factor in 92.6%.

Other studies have similarly found that at human error is involved in 90% of all accidents.

Study #Accidents % Human Error

Treat et al 2258 92.6

Perchonok 670 88%

Finish Insurance Information Center 1193 89%

English Study (cited in Sabey and Staughton) 2130 95%

National Safety Council ? 85%

Treat et al. further found that of accidents caused by human error, perceptual error was involved in 90% and response error in only 10%. If these results generalize to the other studies, then perceptual error is an important factor in over 80% of all automobile accidents.

There are similar estimates for other domains: E. G, Heinrich (1959) Industrial Accident Prevention; Cooper, Newbower, & McPeek, (1978) Preventable anesthesia mishaps: a study of human factors. Anesthesiology, 9, 399; Rothblum (2000) Human Error and Marine Safety, Safety, Maritime Human Factors Conference, Maritime Institute of Technology and Graduate Studies (maritime accidents).

However, these numbers cannot be taken at face value. People often use the term the describe a situation where the driver fails to taken an action that is theoretically possible, without regard to whether that action is reasonable under the circumstances. By reasonable, I mean that the action is within the limits of human limitations, predispositions and expectations. For mundane examples see "Human Error Vs. Design Error."

References

Finish Insurance Information Center (1974) Insurance in Finland.

National Safety Council (1974) Accident facts.

Perchonok, K. (1972) Accident cause analysis. CAL Report. ZM-5010-V-3, Cornell Aeronautical Laboratory, Inc.

Sabey, B. E. and Staughton, G. C. (1975) Interacting roles of road environment, vehicle and road user in accidents. Paper presented at the 5th International Conference on the International Association for Accident and Traffic Medicine, London.

Treat, J. R., Tumbas, N. S., McDonald, S .T., Shinar, D., Hume, R. D., Mayer, R. E., Stanisfer, R. L., and Castillan, N. J. (1977) Tri-level study of the causes of traffic accidents. Report No. DOT-HS-034-3-535-77, Indiana University.