A Guide to Applying the Safe System Approach to Transportation Planning, Design, and Operations (2025)
Chapter: Appendix E: Safe System Law Enforcement Practices
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"Appendix E: Safe System Law Enforcement Practices." National Academies of Sciences, Engineering, and Medicine. 2025. A Guide to Applying the Safe System Approach to Transportation Planning, Design, and Operations. Washington, DC: The National Academies Press.
doi: 10.17226/29147.
APPENDIX E
Safe System Law Enforcement Practices
Appendix E provides data on how respondents appraised various Safe System law enforcement practices. See Table E-1 for scores related to each practice’s feasibility and impact.
Interpretive categorization of Z-scores (Feasibility and Impact columns), with a mean of zero (0) and standard deviation of one (1).
| Categories | Z-scores |
|---|---|
| High | > 1 SD above mean |
| Moderate | < 1 and > 0 |
| Low | > −1 and < 0 |
| Very Low | < −1 SD below mean |
Note: SD = standard deviation round the mean score of zero (0).
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82
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Suggested Citation:
"Appendix E: Safe System Law Enforcement Practices." National Academies of Sciences, Engineering, and Medicine. 2025. A Guide to Applying the Safe System Approach to Transportation Planning, Design, and Operations. Washington, DC: The National Academies Press.
doi: 10.17226/29147.
Table E-1. Enforcement practice feasibility and impact scores (n = 61).
| Practice | Feasibility | Impact | Category |
|---|---|---|---|
| Instituting immediate administrative license revocation or suspension for alcohol- and drug-impaired driving offenses. | 0.225 | 0.424 | Moderate Feasibility/Moderate Impact |
| Instituting or enforcing a statewide primary enforcement seat-belt-use law that would require occupants to wear seatbelts in the front and back seats and allow law enforcement officers to ticket occupants for not wearing a seatbelt, without other citable traffic infractions taking place. | 0.204 | 0.426 | Moderate Feasibility/Moderate Impact |
| Instituting high-visibility saturation patrols for alcohol- or drug-impaired driving. | 0.157 | 0.287 | Moderate Feasibility/Moderate Impact |
| Requiring alcohol ignition interlocks installed for all drivers convicted of driving under the influence. | 0.035 | 0.406 | Moderate Feasibility/Moderate Impact |
| Instituting or enforcing a statewide universal motorcycle helmet law that would require all motorcyclists to wear U.S. DOT–compliant helmets, regardless of the rider’s age or experience. | 0.116 | 0.177 | Moderate Feasibility/Moderate Impact |
| Placing serious crashes in a time- or place-based context when engaging news media partners. | 0.134 | −0.321 | Moderate Feasibility/Low Impact |
| Implementing speed safety cameras (automated speed enforcement) that use revenues to fund safety infrastructure. | −0.170 | −0.061 | Low Feasibility/Low Impact |
| Implementing red-light-camera enforcement that uses revenues to improve safety. | −0.222 | −0.169 | Low Feasibility/Low Impact |
| Linking police with emergency medical services/hospital data for persons injured in motor vehicle crashes. | −0.088 | −0.344 | Low Feasibility/Low Impact |
| Forming a task force or community coalition of law enforcement, transportation, public health, members of the community, and other partners to investigate serious crashes and report findings and proposed changes to the public. | −0.340 | −0.127 | Low Feasibility/Low Impact |
| Encouraging and facilitating public use of self-reporting (via mobile app or survey) to capture collisions and other events falling outside the scope of traditional crash reporting (e.g., near misses, pedestrian and bicyclist falls). | −0.051 | −0.698 | Low Feasibility/Low Impact |
Page
81
Share
Suggested Citation:
"Appendix E: Safe System Law Enforcement Practices." National Academies of Sciences, Engineering, and Medicine. 2025. A Guide to Applying the Safe System Approach to Transportation Planning, Design, and Operations. Washington, DC: The National Academies Press.
doi: 10.17226/29147.
Page
82
Share
Suggested Citation:
"Appendix E: Safe System Law Enforcement Practices." National Academies of Sciences, Engineering, and Medicine. 2025. A Guide to Applying the Safe System Approach to Transportation Planning, Design, and Operations. Washington, DC: The National Academies Press.
doi: 10.17226/29147.
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