"Across-the-road" Doppler photo radars --aimed across a thoroughfare instead of parallel to or alongside it -- are increasingly being used for measuring vehicle speeds on the nation's highways. These devices provide distinct advantages over older radar guns: easier concealment, better differentiation between vehicles, automated identification of offenders using complementary photographic equipment, and best of all for officers - nothing that will triggger a radar detector. Unfortunately, the radars currently also require frequent calibration to ensure their accuracy.
At the request of the National Highway Traffic Safety Administration, the National Institute of Standards and Technology (NIST) has developed calibrator/simulator units that will certify the performance and accuracy of across-the-road traffic radars. The units soon will undergo field tests.
The calibrator/simulator units are self-contained with software that simulates vehicles from motorcycles to trucks over speeds from 24 to 193 kilometers per hour (15 to 120 miles per hour) with an expected accuracy of plus or minus 2 kilometers per hour (1 mile per hour). The calibrator units are reliable, simple in design and should be inexpensive when manufactured in quantity.