Motor Vehicle Injury Alcohol-Impaired Driving: Lower BAC Laws for Young or Inexperienced Drivers

The CPSTF finding is based on evidence from a systematic review of six studies (search period through June 2000).

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.

As of February 2015, all U.S. states had lower BAC laws for drivers under 21 years of age.

More details about study results are available in the published evidence review.

The systematic review included six studies.

• Fatal crashes decreased by 24%, 17%, and 9% (3 studies).
• Fatal and nonfatal injury crashes decreased by 17% and 4% (2 studies).
• Crashes in which the investigating police officer believed that the driver had been drinking alcohol decreased by 11% (1 study).

More details about study results are available in the published evidence review.

• The one study that qualified for the economic review estimated a benefit-to-cost ratio for lower BAC laws of $11 per dollar invested when violators received a six-month license suspension.
  • The study, a cost benefit analysis, applied previously published crash costs and used effectiveness data from other previously published studies to illustrate how these costs could be applied to lower BAC laws in the U.S.
  • The benefits from a reduction in alcohol-related crashes were estimated using the assumption that lower BAC laws reduce young drivers’ alcohol-related crashes by 20%.

These results should be applicable to all young and inexperienced drivers covered by lower BAC laws (in the United States, those under 21 years of age).

CPSTF identified several areas that have limited information. Additional research and evaluation could help answer the following questions and fill remaining gaps in the evidence base. (What are evidence gaps?)

• How do variations in enforcement levels influence the effectiveness of laws to reduce alcohol-impaired driving?
• What are the independent effects of publicity on the effectiveness of laws to reduce alcohol-impaired driving?
• Does public compliance with new laws change in a predictable manner over time?
• How do interventions to reduce alcohol-impaired driving interact with each other (e.g., 0.08% BAC laws and administrative license revocation)?
• What effects do these interventions have on long-term changes in social norms about drinking and driving?
• Are interventions equally effective in rural and urban settings?
• Are interventions equally effective when applied to populations with different baseline levels of alcohol-impaired driving?
• What proportion of youths charged with violating zero tolerance laws had BAC levels elevated enough to warrant a more serious drinking-driving offense?
• Do interventions to reduce alcohol-impaired driving reduce other forms of alcohol-related injury?
• What are the cost-benefit, cost utility, and cost-effectiveness of interventions?
• What role can community coalitions play in removing barriers to implementing interventions designed to prevent alcohol-impaired driving?

• Included studies evaluated the number of motor vehicle crashes from one to 15 years after enactment of lower BAC laws (median 22 months) using the information in police reports.
• Studies reported fatal crashes (3 studies), fatal and nonfatal injury crashes (2 studies), and crashes in which the investigating police officers believed the driver had been drinking alcohol (1 study).
• Studies were conducted in the United States (4 studies, two of which evaluated laws in multiple states) and Australia (2 studies). States studied were geographically diverse, with both urban and rural populations represented.

Effectiveness Review

Analytic Framework see Figure 1 on page 67

When starting an effectiveness review, the systematic review team develops an analytic framework. The analytic framework illustrates how the intervention approach is thought to affect public health. It guides the search for evidence and may be used to summarize the evidence collected. The analytic framework often includes intermediate outcomes, potential effect modifiers, potential harms, and potential additional benefits.

Effectiveness Review

Summary Evidence Table — Effectiveness Review

Economic Review

Summary Evidence Table — Economic Review

The number of studies and publications do not always correspond (e.g., a publication may include several studies or one study may be explained in several publications).

Effectiveness Review

Blomberg RD. Lower BAC limits for youth: evaluation of the Maryland .02 law. Washington, DC: U.S. Department of Transportation, National Highway Traffic Safety Administration, 1992. DOT HS 807 860.

Haque MO, Cameron M. Effect of the Victorian Zero BAC legislation on serious casualty accidents: July 1984 December 1985. J Safety Res 1989;20: 129 37.

Hingson R, Heeren T, Winter M. Lower legal blood alcohol limits for young drivers. Public Health Rep 1994;109:738 44.

Maisey GE. The effect of lowering the statutory alcohol limit for first year drivers from 0.08 to 0.02 gm/100ml (monograph). Perth, Western Australia: Western Australia Police Department, Research and Statistics Section, 1984. Research Report 84/2.

Voas RB, Lange JE, Tippetts AS. Enforcement of the zero tolerance law in California: a missed opportunity? 42nd Annual Proceedings: Association for the Advancement of Automotive Medicine, October 5 7, 1998. Charlottesville, VA. pp. 369 383.

Voas RB, Tippetts AS, Fell J. The United States limits drinking by youth under age 21: Does this reduce fatal crash involvements? 43rd Annual Proceedings Association for the Advancement of Automotive Medicine, September 20 21, 1999. Barcelona (Sitges), Spain. pp. 265 78.

Economic Review

Miller TR, Lestina DC, Spicer RS. Highway crash costs in the United States by driver age, blood alcohol level, victim age, and restraint use. Accid Anal Prev 1998;30:137 50.

The reviews of interventions to reduce motor vehicle-related injury reflect systematic searches of multiple databases as well as reviews of reference lists and consultations with experts in the field. The team searched six computerized databases (MEDLINE, Embase, Psychlit, Sociological Abstracts, EI Compendex, and Transportation Research Information Services [TRIS]), which yielded 10,958 titles and abstracts for articles, book chapters, reports, and published papers from the Association for the Advancement of Automotive Medicine proceedings about safety belts, alcohol-impaired driving or child passenger safety. Studies were eligible for inclusion if:

• They were published from the originating date of the database through June 2000 (March 1998 for child safety seat interventions)
• They involved primary studies, not guidelines or reviews
• They were published in English
• They were relevant to the interventions selected for review
• The evaluation included a comparison to an unexposed or less-exposed population
• The evaluation measured outcomes defined by the analytic framework for the intervention

For alcohol-impaired driving reviews, supplementary searches were conducted to address specialized questions and to update searches for reviews published after 2001. The final search using the primary alcohol-impaired driving search strategy was conducted through December 2004. For the most recent review in this series, “Effectiveness of Multicomponent Programs with Community Mobilization for Reducing Alcohol-Impaired Driving,” this database was supplemented by a hand search of the “Alcohol and Other Drugs” and “Transportation” sections of the SafetlyLit injury literature update service for the period from January through June 2005.

Effectiveness Review

Primary Search Strategy

1. S MOTOR(W)VEHICLE? OR CAR OR CARS OR AUTOMOBILE? OR MOTORCYCLE? OR TRUCK? OR TRAFFIC(2N)ACCIDENT? OR DRIVING OR DRIVER?
2. S ALCOHOL OR ALCOHOLIC(W)BEVERAGE? OR ALCOHOL(3N)DRINKING OR ETHANOL OR ALCOHOLISM OR DWI OR DUI OR (DRIVING(3N)(INTOXICATED OR INFLUENCE OR DRUNK OR DRINKING OR IMPAIRED))
3. S INTERVENTION? OR OUTREACH? OR PREVENTION OR (COMMUNITY(3N)(RELATION? OR PROGRAM? OR ACTION)) OR DETERRENT? OR PROGRAM? OR LEGISLATION OR LAW? OR EDUCATION OR DETERENCE OR COUNSELING OR CLASS OR CLASSES OR HEALTH(W)PROMOTION
4. S FOOD(W)INDUSTRY OR AIRPLANE? OR AIRCRAFT? OR PILOT? OR SOLVENT? OR SLEEP(W)APNEA OR EMISSION? OR AIR(W)QUALITY OR POLLUTION
5. S (S1 AND S2 AND S3 ) NOT S4

Higher Education-based Interventions

S1 MOTOR(W)VEHICLE? OR CAR OR CARS OR AUTOMOBILE? OR MOTORCYCLE? OR TRUCK? OR TRAFFIC(2N)ACCIDENT? OR DRIVING OR DRIVER?
S2 ALCOHOL OR ALCOHOLIC(W)BEVERAGE? OR ALCOHOL(3N)DRINKING OR ETHANOL OR ALCOHOLISM OR DWI OR DUI OR (DRIVING(3N)(INTOXICATED OR INFLUENCE OR DRUNK OR DRINKING OR IMPAIRED))
S3 UNIVERSIT? OR COLLEGE? OR CAMPUS? OR (EDUCATION?(2N)(HIGER OR INSTITUTION? OR FACILIT? OR PROGRAM? OR SURVEY?))
S4 S1 AND S2 AND S3
S5 CURRICULUM OR INSTRUCTION OR EDUCATION OR TRAINING OR WORKSHOPS OR PROGRAMS OR COURSE? OR TEACH? OR (SOCIAL(W)NORM?)
S6 STUDENT? OR YOUTH? OR TEEN? OR (YOUNG(W)ADULT?)
S7 S4 AND S5 AND S6

School-based Interventions

S1 MOTOR(W)VEHICLE? OR CAR OR CARS OR AUTOMOBILE? OR MOTORCYCLE? OR TRUCK? OR TRAFFIC(2N)ACCIDENT? OR DRIVING OR DRIVER?
S2 ALCOHOL OR ALCOHOLIC(W)BEVERAGE? OR ALCOHOL(3N)DRINKING OR ETHANOL OR ALCOHOLISM OR DWI OR DUI OR (DRIVING(3N)(INTOXICATED OR INFLUENCE OR DRUNK OR DRINKING OR IMPAIRED))
S3 SCHOOL?(5N)(BASED OR SETTING OR PROGRAM? OR PRIMARY OR ELEMENTARY OR SECONDARY OR ((JUNIOR OR SENIOR)(W)HIGH) OR MIDDLE) OR (EDUCATION?(2N)(INSTITUTION? OR FACILIT? OR PROGRAM? OR SURVEY?))
S4 S1 AND S2 AND S3
S5 CURRICULUM OR INSTRUCTION OR EDUCATION OR TRAINING OR WORKSHOPS OR PROGRAMS OR COURSE? OR TEACH?
S6 STUDENT? OR ADOLESCENT? OR YOUTH? OR TEEN? OR CHILD? OR TEACHER?
S7 525 S4 AND S5 AND S6

Cost Analyses

1. S MOTOR(W)VEHICLE? OR CAR OR CARS OR AUTOMOBILE? OR MOTORCYCLE? OR TRUCK? OR TRAFFIC(2N)ACCIDENT? OR DRIVING OR DRIVER?
2. S ALCOHOL OR ALCOHOLIC(W)BEVERAGE? OR ALCOHOL(3N)DRINKING OR ETHANOL OR ALCOHOLISM OR DWI OR DUI OR (DRIVING(3N)(INTOXICATED OR INFLUENCE OR DRUNK OR DRINKING OR IMPAIRED))
3. S INTERVENTION? OR OUTREACH? OR PREVENTION OR COMMUNITY(3N)(RELATION? OR PROGRAM? OR ACTION)) OR DETERRENT? OR PROGRAM? OR LEGISLATION OR LAW? OR EDUCATION OR DETERENCE OR COUNSELING OR CLASS OR CLASSES OR HEALTH(W)PROMOTION
4. S FOOD(W)INDUSTRY OR AIRPLANE? OR AIRCRAFT? OR PILOT? OR SOLVENT? OR SLEEP(W)APNEA OR EMISSION? OR AIR(W)QUALITY OR POLLUTION
5. S COST? OR ECONOMIC? OR ECONOMETRIC?
6. S (S1 AND S2 AND S3 AND S5) NOT S4

The CPSTF recommendation and evidence from this review may be used to inform decisions about maintaining lower BAC laws for young or inexperienced drivers. Following are considerations drawn from studies included in the evidence review, the broader literature, and expert opinion.

• Engage partners throughout the process. Building support from the ground up can help secure policies that reinforce healthy behaviors in the community.
• Demonstrate why the policy is important. Use CPSTF findings and recent surveillance data to show partners how policies have been effective.
• Educate stakeholders. Keep the media, community influencers, and policymakers informed about lower BAC laws to help communicate messages that are accurate and timely.
  • Keep messages brief and to the point. Use graphics, figures, or infographics to clearly demonstrate how the intervention can improve health outcomes.
  • Extend your communication reach by working through partners who have the most credibility with key audiences.
• Pay attention to sustainability. Continue to conduct surveillance related to alcohol-impaired driving and disseminate findings.
• Lower BAC laws may be useful in populations other than young drivers. For example, CDC recommends that states consider enacting lower BAC laws for all drivers who transport children.
• Lower BAC laws can result in underage drinking drivers with high BACs receiving only zero tolerance citations rather than being arrested for alcohol-impaired driving (as would drinking drivers 21 years and older).
• Following are potential barriers to full enforcement of lower BAC laws:
  • Because young people are less likely than adults to drink in bars, police patrols that target bar neighborhoods are likely to miss underage drinking drivers.
  • Officers may have difficulty identifying underage drinking drivers with low BACs because they may not show obvious signs of impairment.
  • Because of ambiguities, some state laws prohibit police officers from testing the BAC of an underage driver unless there is probable cause to believe that the driver’s BAC is above the legal limit for adults.

Healthy People 2030

Healthy People 2030 includes the following objectives related to this CPSTF recommendation.

• Reduce the proportion of motor vehicle crash deaths that involve a drunk driver — SU‑11