A review of the scientific literature regarding the effects of alcohol on driving-related skills was conducted. One hundred and twelve articles - from 1981 to 1997 - were reviewed. Results were indexed by BAC and behavioral area and entered into a database. Two separate analyses were conducted. The first analysis determined the lowest BAC at which impairment is reliably present in driving-related skills. The second analysis determined the thresholds of impairment for each of twelve separate behavioral areas. It was concluded that:
Alcohol impairs some driving skills beginning with any significant departure from zero BAC. By BACs of 0.05 g/dl, the majority of the experimental studies examined reported significant impairment. By 0.08 g/dl, more than 94% of the studies reviewed exhibited skills impairment. Specific performance skills are differentially affected by alcohol. Some skills are significantly impaired by BACs of 0.01 g/dl, while others do not show impairment until BACs of 0.06 g/dl. Discrepancies between the reported BAC threshold of impairment within a behavioral area reflected a lack of standardization of testing methods, instruments, and measures in the studies reviewed. All drivers are expected to experience impairment in some driving-related skills by 0.08 g/dl or less.
This document is available to the U.S. public through the National Technical Information Service, Springfield, Virginia, 22161. The Report is also available free of charge courtesy of the National Highway Traffic Safety Administration: View Report