Research Update: Effectiveness of Designated Driver Promotion Programs to Reduce Alcohol-Impaired Driving is Unknown

Ditter S, Elder RW, Shults RA, Sleet DA, Compton R, Nichols JL, Task Force on Community Preventive Services. Effectiveness of designated driver programs for reducing alcohol-impaired driving: a systematic review. Am J Prev Med 2005;28(5S):280-7.

What are Designated Drivers?
The varying definition of a “designated driver” is among the challenges facing researchers who study the effectiveness of designated driver programs. The most common definition requires that the designated driver abstain from alcohol, be assigned before anyone in the group starts drinking, and drive group members to their homes at the end of the event or gathering. Another definition is based on the concept of risk- or harm-reduction. Under this definition, the designated driver needs only to maintain a blood alcohol content (BAC) limit that is under the legal limit. In practice, many people may apply the designated driver concept in ways that are unsafe (e.g., by choosing the person in the group who is least drunk to be the designated driver).

Systematic Review of the Research
Despite the popularity of designated driver promotion programs, few studies have evaluated their effectiveness in reducing alcohol-impaired driving, according to a report published in the American Journal of Preventive Medicine. A team of experts led by CDC scientists, under the oversight of the Task Force on Community Preventive Services—a 15-member, nonfederal group of leaders in various health-related fields—conducted a systematic review of research on population-based campaigns and incentive programs designed to increase the use of designated drivers. The review combines the results of nine peer-reviewed papers and technical reports. (Visit www.thecommunityguide.org for more information.)

Designated Driver Promotion Programs
Population-based campaigns promote the concept of designated drivers through mass media outlets. Only one study from Australia met the criteria for the review. Results showed a 13 percent increase among survey respondents who “always” select a designated driver, but no significant change in self-reported alcohol-impaired driving or riding with an alcohol-impaired driver.

Incentive programs increase the use of designated drivers via drinking establishments offering free incentives such as soft drinks, exotic non-alcohol drinks, food, or free admission. The seven studies that measured the number of patrons who identified themselves as designated drivers reported that incentive programs had a median increase of 0.9 designated drivers per drinking establishment per night. The public health impact of the small increase in self-identified designated drivers at each drinking venue is unknown

Review Results
The review found insufficient evidence of effectiveness to recommend either type of designated driver promotion program (population-based campaigns or incentive programs) due to the limited number of studies, the small effect sizes observed, and limitations of the outcome measures. It is important to note that researchers focused exclusively on programs to promote the use of designated drivers; they did not address the question of whether the use of designated drivers reduces alcohol-impaired driving.

For More Information
To learn more about this and other systematic reviews related to motor vehicle injury prevention, visit www.thecommunityguide.org/mvoi/.