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Detecting Detectors

An 18-wheeler was pulled over in Texas transporting illegal aliens. The driver had a radar detector. A Peterbilt stopped at border checkpoint. It looked innocent. The K9 sniffed out 200 pounds of marijuana stuffed in false bottoms of the fuel tanks. The driver had a radar detector. A Nebraska trooper made a routine traffic stop of a tanker truck on Interstate 80 outside of Kearney. He was a fugitive for armed robbery. The trucker had a radar detector.

Truckers still use detectors. Along with CBs, radar detectors tell them how to avoid speeding tickets and the police.

Radar detector use in commercial vehicles was banned in all states per a directive of the U.S. Department of Transportation in February 1995. “No driver shall use a radar detector in a commercial motor vehicle, or operate a commercial motor vehicle that is equipped with or contains a radar detector.” Radar detector use in cars is legal in all states except Virginia, Washington, DC and U.S. military installations. In Canada, only Alberta, British Columbia and Saskatchewan allow radar detectors.

With heightened concern for domestic terrorism and potentials of 18-wheelers transporting terrorists or dirty bombs coupled with present realities of smuggling illegal aliens, illegal drugs, avoidance of safety inspections, speeding and outstanding warrants, detecting radar detectors in commercial vehicles is crucial for public safety. Now, the USDOT ban on radar detector use in commercial vehicles gives law enforcement probable cause traffic stops when radar detectors are detected.

Radar detectors can be detected. Radar detectors operate as radio receivers tuned to the three RF (radio frequencies) frequencies assigned by the FCC for radar gun speed enforcement, i.e., X-band at 10.525 GHz, K-band at 24.150 GHz, and Ka-band at 33.4-36 GHz. Upon receiving a radar gun signal, radar detectors warn drivers with audible and visual warnings up to three miles from the radar gun.

Radar detectors radiate a signal based on their local oscillator (lo) frequency that can be detected. Older detectors radiated 11.55 GHz. The VG-2 was the first radar detector / detector (RDD) and it looked for detectors radiating lo of 11.55 GHz. Marketed by Kustom Signals, the VG-2 alerts officers with a series of lights and sound similar to radar detector warnings and can detect detectors up to one-half mile based on the radar detector.

The radar detector chess game saw makers changing their lo frequencies to avoid the VG-2. They even tout this accomplishment. Many detectors sprouted a new feature called “VG-2 Alert.” This feature detected the detector / detector before the detector / detector detected the detector...a radar detector / detector / detector.

Meeting this challenge, new radar detector / detectors entered the market, i.e., Spectre from Australia offered by McCoy’s Law Line. The Spectre could now detect all old and new radar detectors. There are about 26 million radar detectors in operation or some 15-20% of drivers use a radar detector. This usage varies with speed limits. Radar detector manufacturers countered and some modified their los to avoid the Spectre. The technological insanity continues.

Before the TXDPS made an RDD purchasing decision, they wanted to test a few devices, a VG-2, a Spectre, a Spectre II and a new RDD entry, the MD-3 from Hill Country Research.

Test vehicles containing radar detectors began at a cone that was one-half mile from the RDDs and drove toward them at 30 mph. When RDDs detected the detectors, the test vehicle was told to stop via radio. Each radar detector approached twice. Some were detected 2,356 feet away. The detection distance was determined using a Kustom Signals, Inc., Pro Laser III. If the radar detector reported a “VG-2 Alert” it was recorded. It must be noted approximately 80% of the 26 million radar detectors on the road can be detected by all three RDDs evaluated.

During the test, over 50% of the detectors used were new models just getting to retail stores. Of the 25 detectors tested, the VG-2 detected 44%, the Spectre II detected 98%, and the MD-3 saw 80%. A new product called the Detector Finder was tested. The Finder is a handheld, battery-operated device transmitting all radar bands with laser. When an officer detects a detector with an RDD in an 18-wheeler, he can key up the hidden radar detector with the Finder in his pocket... “You told me you didn’t have a radar detector... why is it going off?”

Radar detector use is directly tied to speed limits. In states with a 65 mph limit, detector use approaches 20%. As speed limits go down, radar detector use goes up. States with dual speed limits, one for cars and one for 18-wheelers, presents another variable. California restricts 18-wheelers to 55 mph while cars can go 70 mph. Detector use in trucks here approached 18%.

Detecting radar detectors in 18-wheelers is a public safety issue and the new RDDs give law enforcement an essential tool in finding illegally used radar detectors. The US DOT commercial ban on radar detector use ensures officers probable cause for making a traffic stop.

Carl Fors is president of Fort Worth-based Speed Measurement Laboratories, Inc. ( He has over 18 years experience in developing and evaluating radar and laser-based public safety products and can be reached at

Published in Law and Order, Apr 2004

Rating : Not Yet Rated

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