The CPSTF finding is based on evidence from a systematic review of 8 studies (search period through June 2003). The review was conducted on behalf of the CPSTF by scientists from CDC’s Division of Unintentional Injury Prevention with input from a team of specialists in systematic review methods and experts in research, practice and policy related to motor vehicle injury prevention.
Detailed results from the systematic review are available in the CPSTF finding [PDF - 125 KB].
Eight studies qualified for the review.
- Designated drivers per drinking establishment per night: median increase of 0.9 designated drivers (interquartile interval: 0.3 to 3.2; 7 studies)
- Respondents exposed to an incentive program reported a 6.5 percentage point decrease (p <.01) in self-reported drinking and driving or riding in a car with an intoxicated driver (1 study).
An economic review of this intervention was not conducted because the CPSTF did not have enough information to determine if the intervention works.
Applicability of this intervention across different settings and populations was not assessed because the CPSTF did not have enough information to determine if the intervention works.
The CPSTF identified several areas that have limited information. Additional research and evaluation could help fill remaining gaps in the evidence base. (What are evidence gaps?)
The following outlines evidence gaps for two types of designated driver promotion programs: population-based campaigns and incentive programs.
Results from the Community Guide review indicate that there were too few empirical studies of sufficient quality and conflicting results to draw clear conclusions about effectiveness of the reviewed designated driver interventions.
Population-based campaigns to promote designated driver use require more research and evaluation to determine their effectiveness. Although the studies reviewed indicate that incentive programs to promote designated driver use may result in small increases in the number of self-identified designated drivers, much remains to be learned regarding the influence of such programs on the decision to use a designated driver, alcohol-impaired driving, and alcohol-related crashes.
Until we have stronger evidence regarding the effects of incentive programs on these variables, it will be difficult to determine their public health impact. Studies of the effects of incentive programs implemented in drinking establishments throughout a community would be ideal sources for such evidence. Well-controlled studies of this nature would be difficult and costly to develop, but the evaluation of existing community-based, designated driving programs would be very helpful in providing preliminary estimates of the public health benefits of designated driver incentive programs. For example, a planned evaluation of the Townsville Thuringowa Safe Communities designated driver program in North Queensland, Australia may begin to address questions related to program effects on alcohol-related crashes and driver BACs.
Future studies of designated driver programs conducted in individual drinking establishments should consider consistently collecting information on the number of drinking groups in the establishment during the observation period. This information would allow for comparisons across studies. Second, it would also be helpful if such studies were supplemented with qualitative evaluations that examined the effect of incentive programs on people’s choices about selecting a designated driver. For example, debriefing people who identified themselves as designated drivers could help answer the fundamental question of how many of these people were new designated drivers recruited by the incentive program, as opposed to those who would have acted as such even without the program, or would have used other safe transportation alternatives. Finally, if and when there are sufficient data on the effectiveness of designated driver programs, information on the cost-effectiveness of both the incentive and population-based campaigns would be helpful for program planning.