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Back to Archives | Back to July 2011 Contents 

Keeping Our Roadways Safe with Speed-Measuring Devices: The Importance of Maintaining Confidence in Their Accuracy

By Sarah R. Horn, Program Manager, Division of State and Provincial Police, IACP, Alexandria, Virginia

raffic safety is an important element of keeping communities safe, enhancing quality of life, and reducing social harm. Law enforcement has the primary responsibility for protecting a nation’s roadways, a major element of which is speed enforcement. Since the 1940s, law enforcement has used speed-measuring devices, which over time have become more sophisticated, reliable, and accurate. While these devices enhance the efficiency and effectiveness of traffic enforcement operations, it is also critical that the courts and the public recognize this equipment as accurate and reliable.

To help meet this need, the Enforcement Technologies Advisory Technical Subcommittee (ETATS), a subcommittee of the IACP Highway Safety Committee, through a cooperative agreement with the National Highway Traffic Safety Administration (NHTSA), has developed minimum performance specifications for radar and lidar (laser) devices.

ETATS comprises equipment manufacturers, equipment users, and technical specialists. Its primary objective is to develop minimum performance specifications for speed-measuring equipment, maintain a testing program, review emerging traffic enforcement technologies, and publish a conforming product list (CPL). The CPL provides manufacturer and model information on speed-measuring equipment that has been tested and meets NHTSA’s minimum performance specification. Law enforcement agencies wishing to use federal funds for the purchase of speed-measuring equipment are required to use devices listed on the CPL. The document is published by the IACP at

The CPL is a good starting point for agencies looking to purchase speed-measuring devices. Knowing that the device has met the NHTSA minimum performance specification gives purchasing agents the confidence that the devices they are interested in purchasing have passed testing and accurately capture information.

Ensuring the courts’ and public’s confidence is paramount when it comes to speed-measuring devices—in purchasing decisions, in maintaining the equipment, or in defending the use of technology in court or to the public.

To maintain an effective and credible traffic safety program, law enforcement agencies should review and understand the minimum performance specifications and know what devices are listed on the CPL. It is also important that they understand the applicable federal, state, and local requirements associated with the use of radar or lidar, since these requirements are outside the scope of the IACP’s performance specifications. The IACP and NHTSA also encourage all law enforcement agencies to develop a written policy defining their devices’ maintenance, calibration, and testing and to ensure that those standards are followed.

Minimum Performance Specifications

Minimum performance specifications provide a baseline for acceptable speed-measuring device performance. The devices are then tested to ensure they conform to the minimum performance specification (across-the-road radar; down-the-road radar; and lidar) and provide high-quality service. Equipment buyers should use these performance specifications as models to develop purchasing criteria. The IACP and NHTSA recommend that these specifications be incorporated into procurement documents. Devices offered for purchase should, at a minimum, meet these specifications.

Available Product Testing

The IACP has two independent testing laboratories for speed-measuring devices that conduct CPL testing; critical performance testing (CPT); and certification testing.

CPL testing is the first step in evaluating a new radar/lidar model against the relevant minimum performance specification. All new devices must undergo this testing to be listed on the CPL; manufacturers voluntarily submit their speed-measuring devices to the IACP. Devices are thoroughly tested to ensure that they meet or exceed the model minimum performance specification. Once a device passes this testing, it is then included on the IACP’s CPL.

CPL Stage II testing is the second phase of testing a device undergoes once it passes CPL testing. This testing requires a set number of the first units produced for use in the United States to be submitted to the IACP for testing to ensure that during the manufacturing process, the device continues to meet or exceed the model minimum performance specification.

If the device passes both the CPL testing and CPL Stage II testing, it will then remain on the CPL. For a device to continue to be listed, it must undergo annual CPT. The CPT allows for ongoing monitoring of devices to ensure that the device continues to meet or exceed the minimum performance specification for that particular model.

Finally, the IACP provides certification testing for law enforcement agencies that want their existing radar and lidar units recertified through the IACP testing laboratories. This service is provided at a minimal cost to the agency.

For more information regarding the CPL, visit the IACP website and download the latest version of the listing at Police departments that are interested in testing should visit the IACP website and download the Request to Perform Testing PDF at; or contact Sarah Horn at 703-836-6767, extension 215, or by email at ■

Please cite as:

Sarah R. Horn, "Keeping Our Roadways Safe with Speed-Measuring Devices: The Importance of Maintaining Confidence in Their Accuracy," The Police Chief 78 (July 2011): 56.

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From The Police Chief, vol. 78, no. 7, July 2011. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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