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Back to Archives | Back to September 2009 Contents 

Speed-Measuring Devices: The Importance of Maintaining Confidence in Their Accuracy

By Sarah Horn, Program Manager, Division of State and Provincial Police, International Association of Chiefs of Police, Alexandria, Virginia

n the late 1940s, law enforcement began using speed-measuring devices to enforce speed laws and regulations. Since then, technological advances have made speed-measuring devices more compact and sophisticated, thus enhancing the mobility, efficiency, and effectiveness of traffic enforcement. However, when agencies are deciding what enforcement equipment to purchase, one factor to consider is that the courts and the public have confidence in their accuracy and reliability.

To meet this need, the Enforcement Technologies Advisory Technical Subcommittee (ETATS), a subcommittee of the IACP’s 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 is made up of 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 resulting CPL lists speed-measuring equipment that has passed CPL testing, adheres to NHTSA’s model minimum performance specification, and is published by the IACP on its Web site,

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 the purchasing agent the confidence that the devices he or she is 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 a healthy traffic safety program, law enforcement agencies should review and understand the minimum performance specifications and know what devices are listed on the conforming product list. However, agencies must also know any applicable federal, state, and local requirements since these requirements are outside the scope of the IACP’s performance specifications. The IACP and NHTSA also encourage all agencies to develop a written policy defining their devices’ maintenance, calibration, and testing.

Minimum Performance Specifications

Minimum performance specifications provide a baseline for acceptable speed-measuring device performance. The devices are then tested to ensure that they conform to the model minimum performance specification (across-the-road radar, down-the-road radar, and lidar) and will provide high-quality service. Equipment buyers should use these performance specifications as a model 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 established two independent testing laboratories for speed-measuring devices that conduct CPL testing, critical performance testing (CPT), and certification testing.

CPL CPL testing is the first step in having a new radar/lidar model evaluated against the relevant minimum performance specification. All new devices must undergo this voluntary testing in order to be listed on the consumer products list; manufacturers submit their speed-measuring devices to 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 consumer products list.

CPL Stage II Once a device passes CPL testing, it moves onto the next phase, CPL Stage II. 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.

CPT If the device passes both CPL and CPL Stage II testing, it will then remain on the conforming product list. For a device to continue to be listed, it must undergo annual critical performance testing, or CPT. CPT enhances the ETATS program by providing a method to ensure that devices continue to comply with the appropriate model minimum performance specification after being listed. Manufacturers voluntarily submit devices that are in their inventory or are ready for shipment to a customer. This stage allows for ongoing monitoring of devices to ensure that the device continues to meet or exceed the minimum performance specifications for the particular model.

Certification Finally, 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 Web site and download the latest version of the listing at

Police departments that are interested in testing should visit the IACP Web site and download the “Notification to Perform Testing” PDF form at or contact Sarah Horn at 703-836-6767, extension 215, or by e-mail at ■



From The Police Chief, vol. LXXVI, no. 9, September 2009. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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