Review of Effects of Alcohol and other Licit Drugs on Driving-Related Performance

Abstract

A review is presented of the effects of alcohol and licit drugs on performance related to driving. About 20% of persons of driving age use some licit drug, while a much greater percentage drink alcohol. Alcohol is used in combination with another licit drug by about 10% of persons of driving age. Alcohol is associated with about 50% of fatal traffic accidents, 30% of injury accidents and 10% of non-injury accidents. Other licit drugs, such as diazepam, are involved in about 20% of non-fatal accidents. Alcohol combined with other licit drugs, such as diazepam, is involved in about 10% of injury accidents.

The effects of alcohol on driving-related skills is relatively well-documented, but tests on the effects of other licit drugs present variable findings. There is some research which indicates additive or synergistic effects when alcohol is combined with other drugs.

Research to date on the effects of licit drugs alone, and in combination with alcohol, has many limitations. There have been comparatively few studies to test decision-making and perceptual-motor skills, such as used in driving or those involving actual driving tasks.

However, studies indicate that when combined with alcohol, some licit drugs lead to a deterioration in driving-related performance, but a need exists for further research involving more complex driving-related tests and actual driving situations.