1. Auto lock on wrong target – The National Highway Traffic Safety Administration suggest that you disable the auto lock on units that have this function and the newer units no longer have this capability.

2. No tracking history – this recommendation is most often ignored. It’s one that is stressed in the operational manual and its impossible to avoid if you are using the unit in the “instant on” mode. The errors occurs when there are multiple targets in the path of the radar beam and the police officer has not observed the average speed reading nor has he checked for any external interference.

3. Harmonic Error from Phase Lock Loop – This problem is common with moving radar units when the police car is accelerating and the target vehicle is moving at a slow speed, typically under 20 mph and an error can occur in the reading.

4. Terrain error – One common factor in radar units is that they always read in a straight line. They cannot read around a turn or the other side of a hill. In this case, the radar unit may actually be reading another vehicle farther up the road rather than the target vehicle that is going to be issued a citation.

5. Look past error – in this case the radar unit finds a larger vehicle between the patrol car and the targeted vehicle and locks on that one and gives an entirely different reading for an entirely different vehicle.

6. Multiple bounce error – These occur usually when there is an overpass in the vicinity of the chase and the radar beam is reflected off of multiple targets at the same time. The vehicle in question, an overpass, a sign, etc. will result in an improper reading.

7. Reflection error – If the antenna part of a radar unit is hung on the outside of the police officer’s car , the beam can actually hit a side window or part of the window and a false reading results which will throw off the actual reading for the targeted vehicle.

8. Arm Swing Error – When the officer swings the unit up to point at the targeted vehicle, the speed of his arm is added to the speed of the vehicle and throws off the reading generated by the vehicle.

Remember, the most important thing in all this is to NEVER admit your guilt at the scene. If you do, it is much harder to get out of traffic tickets.