This paper considers data from Sweden, Norway and the USA to assess whether driving with low blood alcohol concentrations (BACs) is safe. The statistics in this area are notoriously poorer and unreliable. Even fatality statistics underestimate the true effects of alcohol, because not all fatally injured drivers are checked for alcohol and because BAC levels are not always measured near the time of the accident. In non-fatal accidents, the statistics are based on police reports of accidents, and depend on how far investigating police officers had reason to suspect that drivers had been drinking. Thus curves, derived from accident statistics, that represent accident risks at different BAC levels, are unreliable. However, similar curves, based on case control techniques, are more reliable, and show definite evidence of performance impairment at BACs at or below 0.04%. Several other reviews have also concluded that low BACs still represent increased traffic safety risks. However, most European countries have ignored these findings by adopting a 0.08% BAC limit. Whether a low BAC is dangerous depends on the specific driving situation, but it can be dangerous in demanding situations. Targetting low BACs may not save very many lives but it is still worthwhile.
Abstract