Many Drunk Drivers Not Problem Drinkers

Study Challenges Focus of Prevention Efforts, Recommends Sobriety Checkpoints and Other Measures to Stop Alcohol-Impaired Drivers

A substantial number of drivers with high blood alcohol concentrations (BACs) who are killed in automobile crashes are not problem drinkers, according to a study conducted by the Johns Hopkins Bloomberg School of Public Health and the Insurance Institute for Highway Safety. The study examined the relationship between the drivers’ drinking habits, as reported by family members, and BACs at the time of death. The findings appear in the September 2002 issue of Injury Prevention and suggest that prevention efforts addressing alcohol-impaired driving should target a wide spectrum of drinking drivers in addition to the so-called hard-core offenders with drinking problems who frequently drive while impaired by alcohol and resist changing their behavior.

The researchers defined potential problem drinkers using several different measures. A problem drinker is often defined as someone who experiences emotional or physical problems because of drinking, or who has difficulties with family or work, or has legal or financial problems caused by drinking.

“Our study found a strong association between BACs at the time of death and a history of problem drinking. However, more than 40 percent of the drivers we studied with very high blood alcohol levels were not reported to have either of the two strongest indicators of problem drinking by their spouses, who appeared to be the most credible respondents,” said Susan Baker, MPH, lead author of the study and professor ofhealth policy and management at the Johns Hopkins Bloomberg School of Public Health. 

For the study, professor Baker and her colleagues analyzed the BACs and drinking habits of 818 drivers killed in automobile crashes, using data from the Fatality Analysis Reporting System and the National Mortality Followback Survey, which surveyed spouses and close relatives about the deceased drivers’ drinking habits.

The study found that a substantial proportion of the deceased drivers were not identified as problem drinkers, although there was a strong association between BAC and drinking history. Depending on the problem-drinking indicator, 21 to 61 percent of deceased drivers with very high BACs (0.15 g/dL or higher) met the criteria for problem drinking. About 21 percent of drivers with very high BACs were reported as driving within two hours of consuming five or more drinks at least once a month, compared with 2 percent of those with zero BACs. Relatives described 31 percent of deceased drivers with very high BACs as problem drinkers, compared with only 1 percent of drivers with a BAC of zero. Sixty-one percent of drivers with very high BACs were classified as heavy drinkers, compared with 7 percent with zero BACs.

The legal standard for intoxication in 33 states is a BAC of 0.08 g/dL or higher (two other states will have 0.08 standards starting in 2003). In other states, it is 0.10 g/dL or higher. The study also found that only 7 percent of the deceased drivers had been convicted of alcohol-impaired driving in the three years prior to their fatal crash; 19 percent of the drivers with very high BACs had such a conviction in their driving records.

“In addition to programs focused on repeat offenders or problem drinkers, countermeasures such as sobriety checkpoints should target the broader group of drinking drivers,” said Elisa Braver, PhD, co-author of the study and senior epidemiologist at the Insurance Institute for Highway Safety.

“Drinking histories of fatally injured drivers” was written by S.P. Baker, E.R. Braver, L-H Chen, G. Li, and A.F. Williams. It is published in the September 2002 issue of Injury Prevention.

The study was funded by the Insurance Institute for Highway Safety and the Centers for Disease Control and Prevention.

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