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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation
FHWA Highway Safety Programs

Speed Limit Enforcement

While a properly selected speed limit is hopefully self-enforcing, the reality is that an effective speed limit generally relies in part on enforcement of the limit. The engineering community has four main roles in speed enforcement:

  • Communicate with those responsible for enforcement during the setting of speed limits;
  • Provide data to enforcement officials so they may effectively deploy enforcement resources;
  • Provide and maintain automated speed enforcement (ASE) equipment and technologies (where allowed); and
  • Integrate features in the road design to facilitate speed enforcement (i.e., laybys and median openings that assist enforcement personnel).

Because speed limits and enforcement are intertwined, it is important for the road authority to liaise with enforcement personnel before setting a speed limit for a facility. Enforcement personnel have experience and unique insights into the enforceability of speed limits that may be used to ensure that rational speed limits are applied.

Speed enforcement is essentially a crash countermeasure and therefore benefits from a proper understanding of the persons, place, time, and conditions that foster speeding. Engineering personnel can provide speed and crash data as well as citizen complaints to enforcement personnel so that appropriate enforcement strategies are identified. This data-driven approach to resource deployment can target specific scenarios of speeding or types of speeding activities (e.g., commuters, after-school, racing, deliveries, etc.).

Automated speed enforcement uses equipment to monitor speeds and photograph offenders to produce citations that are mailed to the registered owner of the vehicle. ASE is particularly effective at locations where the roadway geometry or traffic volumes make it difficult to use more traditional methods (e.g., requiring a traffic stop). This strategy requires enabling legislation, if such legislation has not already been passed. NHTSA's Speed Enforcement Camera Systems Operational Guidelines is a useful reference.48

The engineering community is generally involved in ASE, as it requires speed cameras that are maintained by the road authority. In all cases, enforcement personnel need to be involved and an integral part of any ASE activities.

A combination of the various enforcement strategies described above, in addition to engineering and communications countermeasures, may contribute to ongoing compliance with the speed limit. When an effective speed enforcement program is sustained, it can continue to deter speeders. The NHTSA and FHWA Speed Enforcement Program Guidelines is a useful reference.42