How Do Police Speed Guns Work?

Jan 9, 17 by Jorian Goes

How Do Police Speed Guns Work?

If you’re reading this article, it may be likely that you recently received a speeding ticket, or you’re just looking for some general knowledge about how radar or laser guns actually work.

At Ticket Snipers, we “aim” to please. We’ll share with you the difference between radar and speed guns, and tell you a little about how they work.

Radar Guns

As How Stuff Works (Auto) points out, “A normal radar set sends out a radio pulse and waits for the reflection. Then it measures the Doppler shift in the signal and uses the shift to determine the speed.”

How Radar Guns Are Used by Law Enforcement

There are actually two types of radar guns that California Law Enforcement or California Highway Patrol may use to detect your speed. The first of those is car-mounted radar. This allows officers to be stationary or on the move to detect speed. When an officer is using the car-mounted version, he or she will usually have a console mounted under their dash that allows them to see your speed immediately. If you recall how a radar gun works, the only thing that needs to happen in order for your speed to be detected is that any part of your vehicle simply has to pass through the radar’s beam, and it sends back the pulse reading that shows the highest speed it read for about a second or two as you passed through its beam.

The second type of radar guns is a hand-held radar gun. You’ll often see these used by motorcycle police officers or officers pulled over on the side of the road. These units typically contain everything they need, such as the antenna, transmitter and receiver all in one unit and your speed is displayed directly on the unit itself. The biggest difference between a hand-held unit and a car-mounted unit is that, unlike the car-mounted unit that can continuously run radar, the hand-held unit requires the officer to point the radar at a vehicle and pull a trigger for the radar to send the pulse to read your speed.

Laser Guns

Laser guns use reflection time of light instead of a pulse like radar guns use. This would be similar to if you were in a long tunnel and shouted, then waited for your echo to come back to you where you could hear it, but it uses the reflection of light and waits for it to return to its starting point instead.

How Laser Guns Are Used by Law Enforcement

When a law enforcement official uses a laser gun, they are very similar to how a hand-held radar gun is used, in that it also relies on the officer to hold the laser gun, point it at your vehicle, and wait for the reflected light to beam back to the unit and provide your speed. There has been an increase over the last few years in law enforcement using laser guns over hand-held radar guns. Why, you ask? The answer is in the science of how the two different guns provide the information the officer is looking for. A radar’s beam is similar to a flashlight- the farther you point it out from your direction, the wider the light (or beam) spreads. This means that in that wide angle, the officer may pick up more than one vehicle’s speed, or not the vehicle he or she thought the radar was pointed at, allowing for a false speed reading. A laser gun uses a light beam to detect speed where the beam is much narrower than the pulse that a radar gun uses, which often means that the reading tends to be more correct. The downfall to a laser gun, however, is that the officer has to keep the laser gun on the same part of the vehicle while it’s in travel- and they can’t see the beam to know if they’ve accomplished that or not.

Whether you’re reading just to have more knowledge on how radar guns work, or if you needed more insight on how this information might help you beat a speeding ticket, Ticket Snipers is always on your side. If we can be of assistance in helping you fight your speeding ticket, please don’t hesitate to chat with us.