Speeding detection

SIGNIFICANCE: Driving at excessive speeds contributes to one-third of all motor-vehicle accidental fatalities in the United States, causing many injuries and considerable property damage every year. These costs give traffic-law-enforcement authorities strong incentives to detect and punish motorists who exceed posted speed limits.

Exceeding speed limits and driving at excessive speeds in unsafe conditions are both illegal and highly dangerous. Highways and motor vehicles are built for safe motor vehicle operation at the speeds traveled by most motorists. Nevertheless, speeding on American roadways is common and contributes to as many as one-third of all accidents involving fatalities. A 2002 study by the National Highway and Traffic Safety Administration reported that speeding is such a pervasive behavior that about three-quarters of surveyed drivers admitted having driven above posted speed limits, on all types of roads, within the previous month. More than one-quarter of the drivers admitted having violated speed limits on the days they were interviewed.

An ongoing question is why so many American motorists ignore posted speed limits. One possible explanation is that drivers see so little evidence of enforcement that they expect not to be caught. However, the ratio of citations issued to mere warnings to speeding motorists has steadily climbed since 1997, reflecting a public concern with the safety hazards posed by speeding motorists. Speeding is clearly one crime in which deterrence works, and the key to effective deterrence is detecting and punishing speeding drivers.

The Basis of Speed Limits

Posted speed limits are generally designed to meet the needs of 70 percent of all drivers and are enforced with standard deviations of approximately 15 percent. That is, drivers who operate their vehicles at speeds 15 percent above or below the posted ranges are considered to be unsafe and may be cited.

When planned intelligently, speed limits are determined scientifically through the application of traffic engineering principles. Speed limits are enforced with scientific equipment, and speeding convictions are validated by testimony based on the scientific principles underlying such speed-detection devices as radar.

Traffic-enforcement officers are responsible for enforcing traffic codes and citing violations. Their primary focus is often on the most common violation, speeding. There are three primary purposes for stopping speeding motorists. The first is to stop violations of the law for public safety. The second is to deter other drivers from speeding. The third purpose is to change drivers’ future driving behaviors.

The benefits of maintaining traffic safety by reducing speeding are both numerous and obvious: increased safety on the roadways for both motorists and pedestrians, lower insurance costs, lower health care and tax costs, and government revenue generation and gains from asset forfeitures.

Traffic-law enforcement can also play an important role as a crime-solving tool. Because most criminals use motor vehicles for transportation to and from crime scenes, as well as their everyday transportation, traffic officers are often involved in preventing and helping to solve crimes. Traffic stops often detect evidence of more serious offenses. Well-trained, alert, and motivated police officers often intercept criminals whom they stop for simple traffic violations.

Methods of Detection

One of the most effective devices for detecting speeding vehicles is radar, which was originally developed as a military technology during World War II to detect enemy aircraft. Speed-measuring radar works on a similar principle by bouncing radio signals off approaching vehicles and calculating oncoming vehicles’ speed by measuring changes in frequency in the returning signals as the vehicles move toward the radar transmitters. The mere presence of traffic radar can deter would-be speeders.

A modern enhancement to traffic radar is photo-radar, which combines cameras and radar transmitters to detect and photograph speeding vehicles. The pictures taken can be used to identify drivers’ faces and the license plates of their vehicles. That information can be used to send citations to the registered owners of the speeding vehicles.

Bibliography

Grabar, Henry. "The American Addiction to Speeding." Slate, 15 Dec. 2021, slate.com/business/2021/12/speed-limit-americas-most-broken-law-history.html. Accessed 10 July 2024.

Hand, B., A. Sherman, and M. Cavanagh. Traffic Investigation and Control. New York: Macmillan, 1980.

Langford, Les. Understanding Police Traffic Radar and Lidar. Rev. ed. Pleasant Grove, Utah: Law Enforcement Services, 1998.

Royal, Dawn. National Survey of Speeding and Unsafe Driving Attitudes and Behavior, 2002. Washington, D.C.: National Highway Traffic Safety Administration, 2004.

Sawicki, Donald S. Traffic Radar Handbook: A Comprehensive Guide to Speed Measuring Systems. Brasstown, N.C.: Grove Enterprises, 1993.

"Speed Limit Basics." U.S. Department of Transportation Federal HIghway Administration, highways.dot.gov/safety/speed-management/methods-and-practices-setting-speed-limits-informational-report/speed-limit. Accessed 10 July 2024.