Home WORLD A Police Radar Makes Mistakes – How Radar Detectors Get it Wrong

A Police Radar Makes Mistakes – How Radar Detectors Get it Wrong

This is information everybody needs to see and understand, including motorists and the officers running the equipment. Radar and laser guns and their operators still make mistakes. It is estimated that over 25% of all radar tickets are in error. The most noticeable and common mistakes include shadowing, RFI interference, cosine error and mechanical interference.

image/text credit:  CopRadar

Shadow Error happens when the moving radar’s “Low Doppler” incorrectly locks onto a large metal object like an 18 wheeler in front of the patrol car and adds the speed differential to the opposite lane target vehicle’s speed. It’s no secret that radar is an inexact science, often recording inaccurate, if not downright impossible readings.

In the span of just three hours, the radar system in this police cruiser recorded fourteen false speed readings, varying from a 93 MPH garbage truck to a 103 MPH school bus and even a 131 MPH family sedan, none of which appeared to be traveling any faster than the traffic around them, which registered between 50 and 70 MPH for the most part.


There’s a real good chance that driver is going to get a ticket and that will almost certainly hold up in court, when they could, in fact, be traveling within the “buffer” most officers allow motorists to travel above the speed limit.