Uses of Detection Devices in Speeding Offenses

In a prosecution for speeding, the prosecutor has the burden of proving each and every element of the case by competent and credible evidence. Normally, the proof will be obtained by the prosecutor from the testimony of the officer. The basic testimony will convey a visual observation or independent estimate of speed made by the officer, corroborated by a calibrated speedometer reading or calibrated radar unit readout. There are essentially five ways for law enforcement officers to determine speed: (1) pacing the motorist's vehicle with the officer's patrol car; (2) obtaining a time-distance measurement with manually activated time; (3) obtaining a time-distance measurement with automatically activated time distance devices; (4) radar; and (5) laser devices.

Radar and laser technologies have been increasingly used in law enforcement in the last couple of decades. There are basically two types of radar devices; radar that must be stationary to operate and radar that can operate either while stationary or moving. Radar devices compute and display instantaneous target speeds. Laser guns are hand-held devices that can measure the speed of a moving vehicle within one mile per hour. The laser gun's operation relies on the elementary principle of physics that the speed of light is known and constant.

Although laser and radar technology have been repeatedly challenged, most courts have accepted laser and radar speed detection technology as valid. However, this does not mean that the evidence from the speed detection device cannot be challenged. In order for the evidence from a device to be admissible, the prosecutor must show that the operator of the device was qualified to operate the device. Whether an officer is qualified is a factual issue, but must courts have found that relatively short training sessions are sufficient to qualify an officer to use a speed detection device. Further, the device's proper operation can be shown by testimony of the officer that he or she followed the accepted procedures recommended by the manufacturer for operating the device.

Courts have held that for radar evidence to be admissible, it must be shown that: (1) the officer operating the unit had adequate training and experience in its operation; (2) the unit was in proper working condition; (3) the unit was used in an area where road conditions were such that there was a minimum possibility of distortion; and (4) when the radar was used, its accuracy was tested and reliably established. Some courts further require some proof that the motorist's vehicle was the target vehicle.

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