Traffic Tech #183: Literature Review of the Alcohol Highway Problem Updated

Number 183                                                             August 1998

LITERATURE REVIEW OF THE ALCOHOL HIGHWAY PROBLEM UPDATED

It has been 30 years since the Department of Transportation conducted the first comprehensive review of the state of knowledge about alcohol and traffic safety in 1968. Since then, the National Highway Traffic Safety Administration (NHTSA) has sponsored several updates of the research in this area. The newest state of knowledge report focuses on identifying target drivers and situations for alcohol-related crashes.

Mid-America Research Institute prepared a critical review of new literature and data since NHTSA's last update in 1989. The review focused on characteristics of drinking drivers, and drinking driving situations that are associated with increased levels of alcohol-crash risk or incidence. The review covers valid scientific documents from both the United States and abroad in these categories:

People at risk
Blood alcohol concentration (BAC)
levels at risk
Environmental situations at risk
Target group studies

People at Risk

A number of factors have been studied in the recent literature, but only driver sex, age and, to some extent, race, are based on hard epidemiologic data. Male drivers in the 21-34 age group, and drivers who are of the white race constitute the largest percentage of alcohol-impaired drivers in fatal crashes. Recent studies continue to indicate that females are becoming increasingly involved in the alcohol-related crashes.

BACs at Risk

Recent research adds little new knowledge about the role of high BACs in alcohol-related crashes, but it does reinforce the findings of prior studies indicating that a high BAC is strongly related to high crash risk. There is also research to suggest that lower BACs (.01 to .09) are associated with increased alcohol-crash risk and involvement.

Data from NHTSA's Fatality Analysis Reporting System (FARS) indicate that there was a sizable number (3,507) of fatal crashes involving drivers at these lower BACs in 1996. Combining the data from FARS and from roadside surveys that measure the BACs of drivers, suggests a significant relative risk of becoming involved in a fatal crash at BACs in the .05 to .10 range, and a lower, also significant risk, in the .02 to .05 BAC range.

Environmental Situations at Risk

Research in this area is usually limited to examining the day of the week and the time of day of impaired driving incidents, and the types of vehicles used by impaired drivers in fatal crashes. FARS data continue to show that there are more fatal crashes and higher percentages of impaired drivers on weekends than on weekdays. More of these crashes occur late at night and in the early morning hours than at other hours. Passenger cars and light trucks are by far the most frequently involved types of vehicles. Motorcycle operators in fatal crashes are more likely to have been alcohol-impaired than drivers of any other type of vehicle.

Target Group Studies

The literature review indicates that although there is adequate data to define broad groups of people who are at risk of becoming involved in an alcohol related crash, the data are still inadequate for identifying more narrow target groups. For example, there is sufficient data to say that young male drivers should be a target group because they are over represented in crashes. However, there are not enough data to allow us to take this definition further -- for example identifying employment status, educational level, or occupation.

Summary

The authors conclude that nearly all of the useful fatal crash data are from FARS, the only exception being data on involvement as a function of race which are from North Carolina. Information on serious injury crashes comes largely from studies from trauma centers in the U.S. and Canada. Roadside survey data come primarily from the National Roadside Breathtesting Survey (conducted during weekend nighttime hours). The data on DWIs are from a range of studies, including those whose subjects were DWIs who had been sent by the court to alcohol assessment or treatment.

The report includes an index, glossary, and list of reports that were reviewed.

HOW TO ORDER

For a copy of the report, Alcohol Highway Safety: Problem Update (54 pages), write to the Office of Research and Traffic Records, NHTSA, NTS-31, 400 Seventh Street, S.W., Washington, DC, 20590, or send a fax to (202) 366-7096.

U.S. Department
of Transportation
National Highway
Traffic Safety
Administration 400 Seventh Street, S.W. NTS-31
Washington, DC 20590

Traffic Tech is a publication to disseminate information about traffic safety programs, including evaluations, innovative programs, and new publications. Feel free to copy it as you wish. If you would like to receive a copy contact:
Linda Cosgrove, Ph.D., Editor, Evaluation Staff
Traffic Safety Programs
(202) 366-2759, fax (202) 366-7096
mailto:lcosgrove@nhtsa.dot.gov