It is a well established fact that the consumption of alcohol before driving a motor vehicle increases the accident risk. However, the importance of rather low blood alcohol concentrations (BAC) for accident risk is still under discussion. Norwegian studies find that drivers involved in fatal, alcohol-related accidents have on the average rather high BACs, above 0.1%. Some claim that "impairment occurs in most areas at the lowest BAC that can be reliably chemically determined". The question is thus: what effect will a reduction of the legal BAC limit from 0.05% to 0.02% have?