22. How does the officer know which vehicle he is clocking?
The officer is responsible for visually verifying the target vehicle. Cases of mistaken identity are possible if the officer is poorly trained or inexperienced. The more vehicles within the range of the radar, the more difficult target identification becomes. Some new radars have a feature that tells the officer if the target is closing or going away.
23. What is the range of police radar?
This will vary depending on the model of radar, the volume of traffic present, the terrain, and the size of the targets being clocked. Some radars are capable of clocking vehicles over a mile away. The author has used older model radars that under the right conditions could track vehicles at almost two miles.
24. How does the officer go about checking the radar’s accuracy?
The procedures may vary between models. Tuning forks are used to check the radar readings and most radars also have some form of an internal calibration test. These tests are customarily performed at the beginning of a shift and sometimes more often. The tuning forks simulate the Doppler shift of a vehicle at a known speed. Most radars also have means of insuring that the digital display has no burned out elements which could cause a misreading of the numbers. In addition to these tests an officer can check the radar by driving and verifying the indicated speed against a certified speedometer or using it side by side with another radar to ensure they both read the same speed on the same target. Many newer radars also do periodic automatic self tests.
25. Does the radar have to be re-calibrated periodically?
Not unless it is required by department policy or by law. Radars contain solid state electronics and have no higher failure rate than other similarly engineered electronic devices. Most radars will simply cease to function when something goes wrong. In those few instances where a radar continues to work when a malfunction exists the officer operator should recognize that a problem exists and take the unit out of service for repair or replacement.
26. Does the weather affect the radar?
Yes, but usually not to the extent some people might think. By the very nature of the radar’s location inside a police unit they are built to withstand a great deal of shock and temperature and humidity variations. Precipitation may reduce the effective range of the radar by causing the signal to scatter and break up more quickly than in clear air but the accuracy of any reading obtained will be unaffected.  Extremes of heat or cold might have a slight temporary effect on the accuracy of the tuning forks used to test the radar while the radar itself remains accurate.
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