Changes in the incidence of alcohol-impaired driving in the United States, 1973-1986.

Studies of motor vehicle fatality data have indicated that alcohol involvement in fatal crashes has declined substantially in the United States since 1980. To determine the actual incidence of alcohol-impaired drivers on U.S. roads, a national roadside survey using portable breath-testing devices was carried out in 32 localities in the spring of 1986. The same sampling design and survey procedures used in a 1973 national roadside survey were followed as much as possible. The 1986 survey found 3.1% of the late-night weekend drivers to have a blood alcohol concentration (BAC) of 0.10% or more, compared to 4.9% of drivers in 1973. Similarly, 8.3% of the 1986 drivers were at or above 0.05% BAC, compared to 13.5% in 1973. The data indicate that the incidence of alcohol-impaired driving on weekend nights has fallen by one-third or more in the United States since 1973 and that the decline affected most population subgroups.