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Back to Archives | Back to July 2004 Contents 

Does Your Agency's Equipment Pass the Test? Traffic Law Enforcement Technologies

By J. F. Bowman, Captain and Commander, Traffic Division, Fairfax County Police Department, Fairfax, Virginia, and Chairman, IACP Enforcement Technologies Advisory Technical Subcommittee, and P. David Fisher, Ph.D., Professor Emeritus of Engineering, Michigan State University

One of the most important and visible components of a comprehensive traffic safety program is the officer actively engaged in traffic enforcement duties. For most citizens, the officer in action on our highways represents the first and only direct encounter with law enforcement. These encounters represent a significant opportunity for the law enforcement community to build public trust. Secondly, the traffic-related vehicle stop often leads to the detection of impaired drivers, stolen vehicles, and other evidence of criminal behavior.

Many jurisdictions across the country are harnessing enforcement technology and employing it in the field to combat aggressive unsafe driving behavior, rising traffic crashes, and fatalities. One of the most common traffic enforcement tools is radar.

Since traffic radar was first introduced as a tool for law enforcement, it has come under countless attacks, tests, and scrutiny. Today, motorists, prosecutors, and judges can be assured that radar, when used in accordance with the manufacturer's instructions by properly trained officers, is a proven, valid, and precise method of determining a vehicle's actual speed. Radar and traffic law enforcement have come a long way, often through the school of hard knocks. We have learned a great deal over the years with traffic radar, and new technologies are quickly coming on the scene at a rate never before experienced. As such this makes the IACP Enforcement Technologies Advisory Technical Subcommittee a valuable resource for the law enforcement executive.

For more than 20 years, IACP has partnered with NHTSA (the National Highway Traffic Safety Administration), NIST (the National Institute for Standards and Technology), and independent testing laboratories to help ensure that enforcement equipment used for highway safety is trust- worthy when used by properly trained law enforcement personnel. Trustworthy equipment is essential to ensure both public trust and court acceptance of these technologies. IACP's administrative guide recommends that recertification of speed measuring equipment be accomplished at a maximum of three years. IACP's testing laboratories are available to accomplish testing and recertification at the intervals required by a particular agency.

Current Status
NHTSA provides seed funding for IACP's enforcement technologies program and also publishes model performance specifications. NHTSA has published standards for both police traffic radar and lidar (laser). Before these standards are accepted and published, NIST and IACP technical consultants carefully evaluated each of these technologies. Once the standards have been published by NHTSA, IACP establishes independent testing laboratories to test and certify equipment to ensure that the equipment meets the published standards. These testing laboratories participate in the following activities.

Consumer Product List
The testing laboratories test new device models, as well as modified existing models, to ensure that they meet the published standards. If they meet the standards, then they are placed on the IACP's Consumer Product List (CPL). Law enforcement agencies are encouraged to use the CPL as a guide in purchasing equipment. By purchasing equipment that is listed on the CPL, an agency helps to assure that the device will be trustworthy when used by a properly trained operator.

Critical-Performance Testing
Once a model has been placed on the CPL, law enforcement agencies may elect to have newly purchased equipment tested and certified before placing the equipment into service. The testing laboratories perform what is known as critical-performance testing (CPT) on these units and provides the agency procuring the equipment with the Certificates of Calibration. These certificates can be used in court to help establish the legal justification for issuing a particular traffic citation.

Motorists and court officials sometimes ask, "How do we know that the piece of radar or lidar equipment that has been in service for a period of time still meets specifications." The IACP testing laboratories are set up to receive equipment from law-enforcement agencies and perform CPT testing and certification for these units. Once again, these certificates can be used in court to help establish the legal justification for issuing a particular traffic citation.

It is important to note that CPL testing is initiated by the equipment manufacturers that wish to have a particular equipment model placed on the IACP's radar or lidar CPL. The cost of this testing is the responsibility of the equipment manufacturer seeking CPL product acceptance. Both critical-performance testing (CPT) and recertification testing are initiated by the law enforcement agency intending to use the equipment, and the cost of this testing is borne by the agency.

Enforcement Technology Outlook
The IACP Highway Safety Committee has a standing subcommittee known as the Enforcement Technologies Advisory Technical Subcommittee (ETATS). ETATS and its various working groups meet periodically throughout the year to review the current status of the enforcement technologies program and to plan future initiatives. ETATS is composed of technical consultants, equipment manufacturers, and representatives from IACP, the Highway Safety Committee, NHTSA, and NIST.

With respect to the existing enforcement technologies initiatives, namely, police-traffic radar and lidar, ETATS reviews and recommends changes in the standards and recommends IACP's procedures for administering the programs. ETATS is also currently working on standards documents for across-the-road radar (photo radar), photo lidar, and photo red light cameras (intersection safety systems).

Across-the-Road Radar: ATR radar deploys the same Doppler radar technology used in traditional police-traffic radar; but the beam of the ATR radar is directed across the road at an angle to the flow of traffic. Target vehicles are only momentarily in the operational area of the beam. This greatly simplifies the target tracking history, especially in areas where there is heavy traffic. Moreover, ATR traffic units capture the infraction on camera; hence, these devices can be used in either attended or unattended operational modes.

Photo Lidar: The photo lidar combines the traditional police-traffic lidar with a camera. The recorded image provides a visual record of the targeted vehicle, the traffic, and the speed-measurement information.

Photo Red Light Cameras: Photo red light cameras monitor traffic flow at intersections that have traffic lights. These cameras can be used to detect red light violations as well as speeding violations at intersections.

The broad deployment of these new enforcement technologies will further enhance highway safety; however, before these technologies can truly become effective tools in the hand of properly trained law enforcement personnel, they must pass the scrutiny of technical experts familiar with the technology. In addition, these technologies must also receive public acceptance, acceptance by the law-enforcement community and acceptance by the courts. IACP is committed to facilitate the continued use of enforcement technologies and the development, acceptance, and use of advanced technologies. The intent is to provide the law enforcement community with the best possible tools to meet its highway safety program needs. Strictly adhering to a policy of initial testing, certification, and timely recertification will ensure that public confidence is maintained at the highest level. Officers in the field deserve and depend on equipment and tools that are able to pass the test.


  • The IACP maintains a Web site ( intended to provide professional assistance to the law enforcement community on matters related to this issue. The Web site contains the latest Consumer Product Lists for radar and lidar. It also provides information for agencies regarding critical-performance testing (CPT) and recertification testing.

  • Specific questions or comments about IACP's enforcement technologies program can be directed to the program manager, Rick Larson, at or by telephone at 800-THE-IACP, extension 263.

  • Specific questions or comments about the IACP Highway Safety Committee and its Enforcement Technologies Advisory Technical Subcommittee (ETATS) can be directed to Captain J. F. Bowman at or by telephone at 703-280-0551.
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    From The Police Chief, vol. 71, no. 7, July 2004. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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