Use of Safety Belts: Primary (vs. Secondary) Enforcement Laws
Primary safety belt laws allow police to stop motorists solely for being unbelted. Secondary safety belt laws permit police to ticket unbelted motorists only if they are stopped for other reasons such as speeding.
Summary of Task Force Recommendations & Findings
The Community Preventive Services Task Force recommends primary safety belt laws based on strong evidence of their superior effectiveness over secondary enforcement laws in reducing motor vehicle-related injuries and deaths.
Results from the Systematic Reviews
Thirteen studies qualified for the systematic review.
- Nine studies compared states with primary laws to those with secondary laws.
- Four studies evaluated the effect of changing from secondary to primary laws.
- Fatal injuries: median decrease of 8% in primary law states versus secondary law states (interquartile intervals: 3%-14% decrease; 5 studies)
- Observed seat belt use: median increase of 14 percentage points in primary law states versus secondary law states (interquartile intervals: 12 to 23 percentage points; 5 studies)
- Police-reported safety belt use: the effect estimate could not be calculated (1 study)
- Self-reported safety belt use: the effect estimate could not be calculated (2 studies)
These results are based on a systematic review of all available studies led 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 increasing safety belt use.
Dinh-Zarr TB, Sleet DA, Shults RA, et al. Reviews of evidence regarding interventions to increase the use of safety belts. [PDF - 2.85MB] Am J Prev Med 2001;21(4S): 48-65.
Task Force on Community Preventive Services. Recommendations to reduce injuries to motor vehicle occupants: increasing child safety seat use, increasing safety belt use, and reducing alcohol-impaired driving. [PDF - 78KB] Am J Prev Med 2001;21(4S):16–22.
Task Force on Community Preventive Services. Motor-vehicle occupant injury: strategies for increasing use of child safety seats, increasing use of safety belts, and reducing alcohol-impaired driving. MMWR Recommendations and Reports 2001;50(RR07):1-13.
Task Force on Community Preventive Services. Motor vehicle occupant injury. [PDF - 355KB] In : Zaza S, Briss PA, Harris KW, eds. The Guide to Community Preventive Services: What Works to Promote Health? Atlanta (GA): Oxford University Press;2005:329-84.
More Community Guide publications about the Prevention of Motor Vehicle-related Injuries
The findings and conclusions on this page are those of the Community Preventive Services Task Force and do not necessarily represent those of CDC.
The content of publications of the Guide to Community Preventive Services is in the public domain. Citation as to source, however, is appreciated. Sample citation:
Guide to Community Preventive Services. Use of safety belts: primary (vs. secondary) enforcement laws. www.thecommunityguide.org/mvoi/safetybelts/enforcementlaws.html. Last updated: MM/DD/YYYY.
Review completed: October 2000
- Page last reviewed: January 26, 2011
- Page last updated: December 17, 2011
- Content source: The Guide to Community Preventive Services