Drinking drivers with very high blood alcohol concentrations (BACs 0.15 percent or more) often are assumed to be hard-core drinkers who repeatedly drive while impaired. The term "hard-core" implies serious drinking problems and behavior that's hard to change.
But how accurate is this assumption? Exactly how common are so called hard-core, or problem, drinkers among drivers with high BACs? Some answers come from a recent study of the drinking histories of a sample of drivers who were killed in crashes in 1993. A main conclusion is that drivers with BACs of 0.15 percent or higher were far more likely than other drivers to have been problem drinkers. The higher the BAC, the more likely the driver was to have a history suggestive of problem drinking.
This finding isn't surprising. However, there's an important caveat — many fatally injured drivers with very high BACs didn't fit the profile of a problem drinker.
"The estimated percentages of fatally injured drivers with very high BACs who were problem drinkers ranged from 21 percent to 61 percent, depending on what indicators we looked at," explains Susan Baker, professor at the Johns Hopkins University School of Public Health.
Interviews with relatives of the fatally injured drivers were used to assess whether those drivers had indicators of problem drinking. For example, one question was whether the drivers were problem drinkers during the last month of life, based on whether they had any physical, emotional, work, or family problems related to drinking.
Drivers with high BACs were more likely than those with low or zero BACs to have prior convictions for alcohol-impaired driving on their records. But the known repeat offenders were a small minority. Even among drivers with very high BACs, fewer than 20 percent had convictions on their records.
"The larger debate this study speaks to is, what's the most effective strategy for prevention? Some say hard-core drinking drivers are the major problem, so we need tougher sanctions when they're caught," says Institute epidemiologist Elisa Braver. "Then again, relatively few people who drive while impaired are caught, which makes tougher sanctions largely ineffective in reducing the problem. We need to prevent impaired driving before it occurs among both problem drinkers and others. Active and highly visible DUI/DWI enforcement programs, in particular sobriety checkpoints, probably are our best way to deter both groups."