Motor Vehicle Injury Safety Belts: Primary (vs. Secondary) Enforcement Laws
Findings and Recommendations
The Community Preventive Services Task Force (CPSTF) recommends primary safety belt laws over secondary enforcement laws to reduce motor vehicle-related injuries and deaths.
The full CPSTF Finding and Rationale Statement and supporting documents for Motor Vehicle Injury Safety Belts: Primary (vs. Secondary) Enforcement Laws are available in The Community Guide Collection on CDC Stacks.
Intervention
Primary safety belt laws allow police to stop motorists solely for being unbelted. Secondary safety belt laws only allow police to ticket unbelted motorists if they have been stopped for other reasons, such as speeding.
About The Systematic Review
The CPSTF finding is based on evidence from a systematic review of 13 studies (search period through June 2000).
Study Characteristics
- All of the included studies compared laws in the United States.
- Studies compared states with primary laws to those with secondary laws (9 studies), or evaluated the effect of changing from a secondary to a primary law (4 studies). There were no studies of states changing from a primary law to a secondary law.
- Studies were conducted in 49 states and the District of Columbia and looked at drivers and passengers of all ages.
- Reported outcomes included fatal injuries, observed safety belt use, police-reported safety belt use, and self-reported safety belt use.
Summary of Results
The systematic review included 13 studies.
- Nine studies compared states with primary laws to states with secondary laws.
- Four studies evaluated the effect of changing from secondary to primary laws.
- Fatal injuries decreased by a median of 8% in primary law states versus secondary law states (5 studies).
- Observed seat belt use increased by a median of 14 percentage points in primary law states versus secondary law states (5 studies).
- Police-reported safety belt use could not be calculated (1 study).
- Self-reported safety belt use could not be calculated (2 studies)
Summary of Economic Evidence
An economic review of this intervention did not find any relevant studies.
Applicability
These findings should be applicable to all U.S. drivers and passengers.
Evidence Gaps
- What are the age, sex, and racial differences between violators in primary and secondary law states?
- Are primary enforcement laws more or less effective in certain populations?
- Do primary safety belt laws increase or decrease risky driving?
- Do primary laws or enhanced enforcement programs deter alcohol-impaired driving?
- Are primary laws associated with changes in frequency of traffic stops for ethnic and racial minorities relative to the general population?
- What are the cost-benefit, cost utility, and cost-effectiveness of interventions to increase safety belt use?
- How can communities increase public acceptance of primary safety belt laws?
Implementation Considerations and Resources
- 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, and explain how strengthening them could further improve health outcomes in their community.
- Educate stakeholders. Keep the media, community influencers, and policymakers informed about safety belt 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 communication reach by working through partners who have credibility with key audiences.
- Pay attention to sustainability. Continue to conduct surveillance related to safety belt use and disseminate findings.
- Adults who use safety belts are more likely to buckle up their child passengers.
- One possible negative effect of primary safety belt laws is the potential for enforcement officers to stop drivers based purely on race or ethnicity. However, studies examining the issue have found no evidence that primary belt laws contribute to such differential enforcement or racial profiling.
- Perceived public opposition to primary safety belt laws may be a barrier to their implementation. Infringement on personal freedom and the potential for differential enforcement are concerns most often cited. To increase public acceptance, some states have included anti-harassment language in their primary safety belt laws.
Crosswalks
Healthy People 2030 includes the following objectives related to this CPSTF recommendation.