Detection, Inspection, and Enforcement Technologies

4. Traffic Enforcement Technologies

Police traffic radar devices have been used in this country to detect speeding motorists since the 1940s. Since then, radar devices have evolved from clumsy, stationary models into sophisticated, microprocessor-enhanced units capable of monitoring vehicle speeds in either direction from moving patrol cars, and into automated across-the-road systems that automatically capture images of speed-offending vehicles. The successful application of radar technologies to speed enforcement has spawned interest in the development of laser technologies, such as lidar devices and photo-lidar systems that photographically document speed violations, as well as an interest in intersection safety systems that record red light violations. Against this bewildering array of technically complex speed-enforcement tools, law enforcement administrators are forced to make difficult procurement decisions.

Figure 20. Police officer using a lidar.

Standards for traffic speed measuring devices are constantly being updated to keep pace with the enhancements manufacturers introduce into their products to improve the ability of law enforcement officers to catch speed offenders on our nation's highways and roads. In addition, a new standard is being prepared for detection systems that capture information of light violations at traffic-light controlled intersections.

Through the development of minimum performance standards, and testing programs administered by the International Association of Chiefs of Police (IACP), baselines are established for acceptable device and system performance. This gives courts and law enforcement officers the assurance that those product models, determined by test to comply with the specifications, will provide accurate and defensible information. To further this program, it is recommended that equipment buyers incorporate these performance specifications into their procurement documents, requiring that units offered for purchase meet or exceed the requirements of the performance specifications. This is intended to encourage manufacturers to produce better devices and systems. Since device features are constantly evolving, the specifications are subjected to continuing review.

4.1 Down-the-Road (DTR) Radar

Figure 21. Police officer using a down-the-road radar.

DTR radar is the speed enforcement technology that is the most widely used throughout the US and the world. There are over 100,000 units in service in the US.

Goals

To develop a reference measurement capability for DTR radar to which the IACP testing labs can compare measurement results. To determine if the existing DTR performance requirements and test methods should be updated, and revise as necessary.

Customer Needs

The customer includes both the court systems and the general public. The courts, as well as the public, want to be very certain that speed violation assessments given to motorists are accurate.

Technical Strategy

• Establish DTR radar performance measurement capability at NIST.
• Determine if existing test methods and performance requirements need to updated.

Deliverables

• Test facility.
• Suggestions for possible modifications.

4.2 Red Light Camera Systems (RLCS)

Figure 22. Street sign warning that an intersection has a red light camera system.

RLCS are becoming increasingly more popular as a mechanism selected by local jurisdictions for ensuring traffic safety at light controlled intersections.

Goals

To develop a reference measurement capability for RLCS to which the IACP testing labs can compare measurement results. To develop RLCS minimum performance requirements and associated test methods.

Customer Needs

Installations of RLCS are increasing in many states across the US. These systems are used for unattended monitoring and control of traffic through light-controlled intersections. The courts, as well as the public, want to be very certain that red light traffic citations given to motorists are valid, unnecessary information is not acquired, and attributing of a citation to an individual is correct.

Technical Strategy

• In collaboration with the Enforcement Technologies Advisory Technical Subcommittee of the IACP, develop minimum performance requirements and associated test methods.
• Establish RLCS performance measurement capability at NIST.

Deliverables

• Minimum performance requirement with test methods.
• RLCS test capability.

4.3 Maintenance of Test and Evaluation Program

Goals

To develop and maintain the International Association of Chiefs of Police test and evaluation program for traffic enforcement devices and to assist the IACP with administering this test and evaluation program for each type of traffic enforcement device for which the IACP has a minimum performance requirement.

Customer Needs

As with all traffic enforcement devices and systems, the courts, as well as the public, want to be very certain that traffic violations given to motorists are valid. As extant traffic enforcement technology changes and improves, and as new technologies are introduced into the traffic enforcement arena, the required test methods and measurement process must keep pace. Furthermore, as costs of test increase, new ways must be sought to ensure the testing program is effective and efficient as possible.

Technical Strategy

• Evaluate suggested electromagnetic interference test procedures
• Develop complex sampling regime that can maintain current assurances of device performance yet reduce cost of test

Deliverables

• Maintenance of up-to-date minimum performance specifications for traffic enforcement devices and systems.
• Development of an intersection safety system standard.
• Assistance to the IACP with administration of its device and system Compliance Testing Program.