This all started with Florida v. Aguilera in 1979. It is known as the National Radar Trial. Judge Nesbit took the Court into the field and observed a palm
tree clocked by a police radar gun at 86 mph. He dismissed many speeding cases. The Court ruled that: (1) radar may deliver false readings and (2) operator training is often inadequate and inappropriate.  The ruling resulted in all radar guns be laboratory tested by then the National Bureau of Standards, now National Institute of Standards and Technology (NIST), testing of radar by the International Association of Chiefs of Police, IACP to include development of a Consumer (Conforming) Products List of tested and approved police radar devices. See Now we have federal performance specifications for both radar and laser guns of DOT HS 809 812 for radar and DOT HS 809 811 for laser. Radar stands for RAdio Detection And Ranging. Laser stands for Light Amplification by Stimulated Emission of Radiation.

Depending on the state and/or local written policy, radar guns should be checked for accuracy with tuning forks on a daily basis.  Before using any radar or laser gun, we tested them with tuning forks and a Known Distance / Vertical / Horizontal Sight Alignment test for laser guns. There should be a log of the testing maintained by the officer. This is advised for in the Operators Manual of the radar gun manufacturer. The manuals say periodic checks should be made of the radar/laser gun’s accuracy called a Known Speed Test. This is done by having other officers, in radio communication, approach the radar gun at a Known Speed, usually by putting the car in the cruise control mode. Re-certification of the radar gun is made by an identified re-certification company and/or the manufacturer. This re-certification period is dependent on the written policy of the local police agency.

Training of officers, certification to operate a police radar or
laser guns, varies widely. NHTSA only has the power of recommending curriculum for training. Training is a state issue according to NHTSA. In Texas, the Texas Transportation Code, Chapter 644, Subchapter C, (d) said: “ A sheriff, a deputy sheriff, or any police officer that does not attend continuing education courses on the enforcement of traffic and highway laws and on the use of radar equipment as presented by Subchapter F, Chapter 1701, Occupation Code, shall not enforce traffic laws.” This received a negative, Opinion No. JC-0497, by the Texas Attorney General of April 29, 2002 stating: “A peace officer is not currently required by section 644.101 (d) of the Transportation Code to attend continuing education courses regarding enforcement of traffic and highway laws and the use of radar equipment.”

The prima facia, best evidence, in any radar/laser trial is the officer’s observation of the speeding, offending vehicle. This is called a Valid Visual Tracking History. The officers must be able to identify the make and model of the offending vehicle and estimate the speed of the vehicle. Radar/
laser readings only confirm the officer’s observation. This means officers must be able to visually identify specific vehicles which is difficult if not impossible at distances greater than ¼ mile. This was mandated when radar was young. In December of 1966, Honeycutt v. Commonwealth of Kentucky, Ky. S.W. 2d 421, the court of appeals said: “that the instrument was tested within a few hours of its specific use, and found to be accurate by the use of calibrated tuning forks…the officer need not understand the scientific principles of radar or be able to explain its internal workings.” This has been affirmed by many courts since 1966. In The Court of Criminal Appeals of Texas, September 16, 2009, the Court said the officer’s probable cause to make the traffic stop was based solely on the reading of the laser gun without a Valid Visual Tracking History. The Court mandated that the officer must have a Valid Visual Tracking History prior to the use of radar or laser gun speed readings. The case against the defendant was dismissed. It doesn’t stop here. The Ohio Supreme Court in Barberton v. Jenny, Barberton v. Jenny, 126 Ohio St.-3d 5, 2010-Ohio-2420. concluded the “police officers unaided visual estimation of a vehicle’s speed is sufficient evident to support a conviction for speeding without independent verification (radar/laser speed reading) of the vehicle’s speed.” This State Supreme Court decision was quickly followed by a law emanating from the Ohio Senate, 4511.091 allowing the use of radar and laser gun speed readings after a Valid Visual Tracking History was made by the officer.

In our research, we want to
observe several things. What is the maximum range of radar guns when used on a white Chevrolet HHR approaching? What is the maximum range in the speed/distance setting of laser guns of the HHR approaching and receding from the laser guns? We also wanted to observe if radar and laser guns produced the same speed target on the same vehicle at 500 feet. Remember, radar and laser guns are operated by certified police officers only. Officers or SML staff members were in the target vehicle to record the results. Results were also recorded in the transmit vehicle.

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Radar/Laser Gun Accuracy/Range