Radar v. Laser – How They Work and Are They Reliable

Posted Friday, April 5, 2019 by Andrew Charles Huff

A Radar speed measuring device directly determines a vehicle’s speed by measuring the doppler (speed induced) shift of the return of its transmitted frequency. For example, the sound you sometimes hear of an approaching or receding train or emergency vehicle.

How does police radar operate?

Police radar can be operated in two modes. The first is continuously transmitted or constant-on (CO) operation. Police utilize “speed traps” using constantly transmitting police radar that are designed to be harder to detect by radar detectors. Police can operate constant-on radar from a “covered” position—hiding amongst heavy foliage of a median, for example, and pointing their gun across the roadway at an angle—not directly at approaching vehicles.

The second mode of police radar operation is called RF-hold, more commonly known as instant-on radar or IO radar. This method of police radar operation began to appear in the early 1980’s as radar detector usage grew in popularity and it’s designed to specifically defeat drivers who operate a radar detector.

What types of police radar are used?

Police radar guns operate on three frequency bands: X-band, K-band, and Ka-band. Most newer police radar guns operate on the super-wide Ka-band. K-band is still quite common, given its historical advantage to Ka-band. The oldest X-band radars are slowly being supplemented with newer and smaller digital (DSP) Ka-band radar and even more lethal police laser guns.

How is police radar used from a patrol car?

Police radar can be operated in a stationery position or moving vehicle. Washington state allows radar to be operated by a patrol officer while driving or “moving mode.” Some police radar units that are mounted to patrol vehicles have two transmitters, one pointing forward and one pointing towards to rear. The rear facing transmitter can easily clock vehicles that are following a patrol vehicle so be mindful when approaching a patrol car on the highway.

Is radar accurate?

The short answer is yes, it’s very accurate. Sometimes radar’s performance can be reduced during times of inclement weather, but that doesn’t reduce accuracy, just effective targeting ranges.

How far can my speed be determined by radar?

Generally speed measurements are taken when you are within a 1000 feet and sometimes closer when an officer hides in a stationery position.

How is laser different from radar?

Today’s laser guns provide the same advantages of stealth operation and offer very quick acquisition of speed.

Radar is not particularly efficient at determining a single vehicle’s speed when there are many vehicles on a crowded highway. With laser, the officer can specifically target your vehicle in much the same way a sniper with a scope does.