NCJ Number
74221
Journal
Police Chief Volume: 47 Issue: 12 Dated: (December 1980) Pages: 57-61
Date Published
1980
Length
5 pages
Annotation
This article examines two types of speed measuring equipment used by law enforcement agencies: equipment based on the radar/doppler effect principle; and equipment based on the distance travelled/time recorded principle.
Abstract
Stating that only continuous wholesale speed checking will substantially reduce petroleum product consumption and increase road safety, the article describes the operating principle behind devices based on the radar/doppler effect; the advantages and disadvantages of European and American radar equipment; and some particular problems of American radar including the existence of outside interference. The article briefly discusses a recent Miami court ruling that radar is inexact and often unreliable; performance standards for various police speed measuring devices, including radar; problems created by moving radar and radar detectors, and the advantages and disadvantages of systems based on the distance travelled/time recorded principle. Advantages and disadvantages of the following three system alternatives are discussed: when the distance is measured by a surveyor or by a traffic police officer; when the time, as well as the distance, is manually measured by a traffic officer driving a patrol car, and when a very short distance (not more than a few meters) is measured by two traffic policemen with an assized tape on both sides of the road and when the timing is started and stopped automatically by the vehicle itself. Finally, the article reviews the use and limitations of two automatic equipment sensor systems: coaxial cables and pencil-thin rubber tubes. Diagrams are included.