[Changes in the spectrum of alcohol-induced traffic accidents in relation to blood alcohol level]

A retrospective study was undertaken to determine whether the degree of alcohol intoxication has an effect on the driving performance with regards to both the quantity and quality. A total of 625 accidents caused by drivers who were under the influence of alcohol were reviewed. They were divided into three groups according to the blood alcohol concentration (BAC):0.30 - 1.09 g/kg, 1.10 - 1.99 g/kg and > 2.00 g/kg. In order to exclude the influence of factors unrelated to alcohol, the groups were matched for age, sex, location of accident and the light and road conditions. This resulted in a total of 85 accidents in each group. The accidents were classified with reference to the "Register of causes of accidents" used in road accident statistics. The three groups differed significantly in their causes of accidents (p < 0.025), although those due to speeding dominated in each group. In the group with low BAC, the next most common accidents were the ones caused by failure to give way. In the group with medium BAC, rear-end collisions and accidents occurring during low speed manoeuvres were the second most common. In the group with highest BAC, the next most common causes of accidents were the leaving of the correct traffic lane unassociated with speeding.