How Radar Detectors Work

Picture this scenario:  You’re cruising down the highway with your family, enjoying the lush greenery surrounding the open road.  A game of eye-spy is heating up as you look around the landscape, trying to find a spot of yellow your daughter has found on the road trip.  Before you know it, you spot a state trooper, his badge reflecting off the afternoon sun, and a radar gun pointed directly at your vehicle.  You panic, looking down at your speedometer; that’s when you realize you’re doing a couple miles over the speed limit.  Your hands clam up and before you know it, POOF! You’re being pulled over. 

So, how exactly do these radar guns work? Well, “Radar” is an abbreviation for Radio Detection and Ranging.  Speed Trak Police Radar can be found in almost every police vehicle.  It’s estimated that 20 million speeding citations are issued annually and that police radars are used in 13 million of these cases. 

Radar Guns send out a signal of radio waves at specific frequencies in a specific direction.  Then, those waves bounce off objects, including vehicles, and return to the radar gun’s receiving station.  When the waves reflect off a moving vehicle, a measurable frequency shift, called Doppler Shift, occurs.

So, police radar guns perceive a vehicle by transmitting a pulse that reaches the target and then comes back to the observer.  What ensues is the Doppler Effect, in which the frequency of the pulse is compared to the frequency of the reflection and speed is calculated using the difference.

And…that’s how it’s done!  Had any crazy radar gun experiences?  Feel free to comment