Different Types of Radar and Laser Police Use to Detect Speeding

Wednesday, November 4, 2009


All of us have seen a cop on the side of the road holding a radar / laser gun to detect speed, but there are different types of radar and laser that you should be aware of and we will go over some of the technology behind them. Do radar / laser detectors really work? We want to educate you on the different types of radar and laser detectors and what you can do (if anything) to protect your wallet from a hefty speeding ticket.

Laser or Lidar

The newest way for the cops to clock you as you cruise down the freeway is using a laser or LIDAR gun to detect your speed.

The primary difference between LIDAR and radar, is LIDAR uses much shorter wavelengths of the electromagnetic spectrum, typically in the ultraviolet, visible, or near infrared range.

Police laser uses laser light pulses rather than radar radio waves for speed detection. The laser speed gun has found its way into the hands of state and local police in at least half the country.

The advantages of a laser gun are compelling: the laser light beam is far narrower than a radar beam, allowing more accurate pinpointing of a specific vehicle; and the time needed for capturing a speed reading is less than half a second versus 2 to 3 seconds for radar.

The drawbacks are also important to note: laser guns are very expensive, they can’t be used from a moving vehicle or from behind glass, and accurate aiming requires a tripod or a very steady hand. cop_laser_gun

Jamming Laser or LIDAR?
There are no Federal laws against the transmission of infrared light. Therefore, laser jammers are legal in most states except while on a military base and/or in a commercial vehicle weighing over 10,000 pounds. States that have banned the use of all jammers include California, Colorado, Illinois, Minnesota, Nebraska, Oklahoma, Utah, Virginia, and Washington DC.

The Problem with Detectors
For starters, they are expensive. The V1, retails at about $399. Secondly, by the time the detector beeps to warn you of a speed trap, it’s too late. The laser gun is “instant on”, meaning the gun isn’t detectable at all times, only when it’s directed at your car. The second the beam hits your car, the laser instantly reads your speed, and that’s what causes the detector to beep.

Why Trapster Works
Trapster does not depend on detecting laser. Trapster is crowdsourced, meaning Trapster’s 12 million users enter locations of speed traps, in turn sharing the location with all other users. This is a win win situation because the motorists will slow down when alerted of a trap, and that is exactly what the police want.

“It’s not hurting our job for public safety. When they put that stuff out there, they slow down at that spot we are at. It is actually helping with public safety.”
– Gabriel Medrano, Texas Dept. of Public Safety



Police have been using radar guns to detect the speed of vehicles since the 1950’s. There are a few different bands of radar used to determine speed, which makes it difficult for drivers to be able to detect them all, or detect the newest band for the cops to use. For information on all the radar bands police are using, see the next section “Different Bands of Radar”.

How to Detect cops Using Radar Guns

A radar detector is a passive electronic device used by motorists to determine if their speed is being monitored by law enforcement agencies via a radar unit, thereby potentially avoiding prosecution for speeding. Only doppler radar-based devices can be detected. Most of today’s radar detectors detect signals across a variety of wavelength bands — usually X, K and Ka (as well as Ku, in Europe.)

Radar Jammers

Radar jammers work on the principle of interfering with or overwhelming the doppler shift that occurs from the reflected radar beam that police RADAR guns require to obtain a vehicles speed.

Unlike police laser (at least in most states), police RADAR can not be legally jammed, in fact, any attempt to do so (whether one is successful or not, most active radar jammers are not) is a federal offense and violates FCC regulations. Simply put: you can be sent to jail if caught using a radar jammer.

Why Trapster Works
Trapster does not depend on detecting radar. Trapster is crowdsourced, meaning Trapster’s 2.5 million users enter locations of speed traps, in turn sharing the location with all other users. This is a win win situation because the motorists will slow down when alerted of a trap, and that is exactly what the police want.

“Having (motorists) slow down on their own is a lot less manpower-intensive than having us forced to spend time writing tickets. Whether they slow down because their friend told them to slow down (by using Trapster) or a ticket, the net effect is the same: They’ve slowed down.”
– Sgt. Brent Barbee, Amarillo Police


Different Bands of Radar

For those who want to dig deeper, here’s some technical jargin and history about different bands of radar.

The X-band frequency is allocated for police radar: 10.5 – 10.55 GHz. It dates back to the 1950s and is the easiest band to detect because of its lower frequency and higher power output. Depending on terrain, temperature, and humidity, X-band radar can be detected from a distance of 2 to 4 miles, yet it only takes accurate readings of speed from a distance of 1/2 mile or less.

K-band is the most frequently used radar frequency band: 24.05 – 24.25 GHz. K-band made its appearance in 1978. The first K-band hand-held radar guns could only be used from a stationary position. Later, a “pulsed” version was introduced that could be used from a stationary or moving vehicle.

K-band radar waves have a relatively small wavelength. At the power level found in police radar guns, K-band has an effective clocking range of about 1/4 mile. Depending upon terrain (around a corner, over a hill, etc.), K-band waves can be detected from a range of 1/4 mile to 2 miles.

In 1987 the FCC allocated a frequency on yet another band, Ka, for police radar use. Ka-Band incorporates Ka-band, Ka Wide-Band, and Ka Super Wide-Band. With Ka came the introduction of photo radar (also known as “photo-cop”). The photo-cop system works at 34.3 GHz and combines a Ka-band radar gun with an automated camera (see Photo Radar below).

The FCC later expanded Ka-band radar use to a range of 34.2 to 35.2 GHz. This became known as Ka Wide-Band.

The introduction of the “stalker” radar gun raised the stakes in the detection game. Unlike all previous guns, the Stalker can be FCC licensed for any frequency in the Ka-band between 33.4 GHz to 36.0 GHz, and so cannot be picked up by detectors designed only for X, K, and photo radar. Today, Stalker guns are being used in more than half the country.

In response, manufacturers have developed detectors with “Super wide-band” technology that sweeps all of the Ka-band allocated to radar, as well as providing continued protection against X, K, and photo radar.

Ku-band radar ranges between 12 and 18 GHz. It is used primarily in Europe for satellite communications, in both aerospace and broadcasting. In the radar enforcement realm, Ku is set at 13.45 GHz by the FCC and has only recently been introduced to the U.S. for speed detection.

How to Stay One Step Ahead

We hope we have helped educate you on the different methods police use to detect your speed when setting up a “speed trap”. If you plan on buying a radar detector, laser detector, and/or laser jammer expect to spend between three and five hundred dollars. But remember they are not legal in all states. There are other tactics like using a CB radio to communicate with other drivers on the road to get a heads up on speed trap locations. Some people use all of these devices to protect themselves while traveling. See one of our Trapster users in action using multiple devices to avoid a speeding ticket, Trapster Videos from Our Users.

More info and sources: radardetector.net Wikipedia, Crutchfield Learning Center

Creative Commons photos from Flickr: DSCN0362 by aslinth, live police photo from gdoolittle

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  • trapster

    We are not qualified to answer this one. But if we find out, we will post it here. Thanks!

  • TJ

     I don’t think an unsteady hand would result in a difference that large. Cops are also trained on how to operate and most use their car, door, etc to prop up and steady the gun.

    The best defense against laser is to check the distance used (the farther away the large the “target” becomes and see if your state has even approved Laser as an appropriate means of evidence. Most have not.

  • Bill Keegan

     If the Ultralyte 2020 doesn’t get at least 70% of the pulses back from the target,it will not show a speed.Speed is not measured but calculated from the time that it takes for the signal to return from the target…

  • Sean

    Very unlikely.  Most ways to end up with notably erroneous readings (more than +/- 0.5 MPH) result in a reduced reading, not increased, and involve either being at a significant angle to the movement direction of the target (sitting far off the road) or targeting the wrong area on the vehicle.

  • Sebsibe

    the  national road saftey council need to purchase some radar with fully accessories like camera mounted and car plate register. could you inform us to get thise ?

                       sebsibe abebe,  Road saftey speed controller.

  • king

     but anyway i use blinder m47, those lasser gun don’t work for me kakak

  • JR

    FYI as of September 1, 2011, it is now illegal in Texas to use, or attempt to use, a Laser/LiDAR blocking device.

  • Rene

    A Virginia patrol officer pulled me over said I was going 92 in a 70 mph zone I knew this was untrue because I was not going that fast, plus as I was driving I just happened to look at my rearview mirror saw his lights looked at my speedometer it said 82 I pulled over to right hand side thinking it was not for me who then moved to the right(mind you I had other cars around me) then he told me that he had me ON VIDEO going 92? Is there such a thing as a video system that catches your speed? SOrry so long.

  • Sam

    In wa. State how often are radar guns supposed to be calibrated and by whom?

  • shl

    all radar bands and laser require the operator to focus on the clocked vehicle headlights as the headlights construction provide a parabolic reflector that efficently returns the clocking signal to the radar/laser gun. The other surfaces of the vehicle do not do this, the clocking signal bounces off them in at oblique angles and is lost. Some time back a group developed a clearcoat spray paint containing particles of reflective material which “masked” the headlights making the vehicle significantly less dectable, and giving the driver (and radar detector) a greater window of reaction time. google it.

  • Pammy

    I was pulled over by state trooper, saying I was going 68 mph in a 45 mph zone. He clocked me on radar as he was coming in the OPPOSITE DIRECTION!!! I know I wasn’t going that fast, so is it possible (since we were both traveling) his radar put out an incorrect reading because of that?
    Thanks for any imput!

  • Marko

    Most police cars have equipted speed monitoring devices on dashboard. they have the technology to clock you while they are moving and you.

  • Tom

    @Pammy, all that has to be done to get an accurate speed on your car (if the officer is traveling in the opposite direction) is to subtract the speed of the officer’s car from the speed the radar detector picks up on yours. I’m almost positive that this technology is implemented in officers’ cars. Even if it isn’t, all that would have to be done is simple arithmetic to calculate your actual (or estimated) speed of your car.

  • Joyce

    I was traveling on hwy with posted speed of 70 mph. In one tenth of a mile from the posted sign of 70 mph, the limit sign dropped to 50 mph. I was clocked by radar as goimg 63 mph from a police cruiser which was approximately 3 tenths of a mile from to posted 50 mph sign traveling in the oposite direction from me. My question is, how can I determine just where, within that one tenth of a mile, could the reading have been taken.

  • Jacob Rasberry

    You got trapped, a cop can legally lie to you, however in municiple court (if you choose a trial) he must show all evidence he has, which is why every time i get pulled over i record the cop, anyhow, you need to bring up the speed detecting video, and point out that there is no such thing.

  • Jay D. Anderson

    If the officer was using RADAR to detect your speed in traffic then he has it set to “fastest vehicle” and he tried to ascertain by eye which vehicle is going faster. This is fraught with error. Large panel trucks further away can produce a stronger signal that you and they may be speeding — that is the speed he will be measuring and attributing to you. If the officer was using LiDAR he may have “swept” the beam from down the side of your car to a car behind you and then you. What would happen then is that since LiDAR calculates your distance over several pulses by measuring their time-in-flight. Since the initial pulses were the car behind you and then you the LiDAR will “think” you traveled a greater distance over that period of time and display a falsely high speed. The devices can easily be mis-used and often are mis-used even by trained police officers. It is a rip off of the American public and a revenue maker for Gov’t — a Gov’t scam if you ask me.

  • Jay D. Anderson

    No. The RADAR can measure speed by looking at the doppler frequency shift in either direction and it subtracts the officer’s speed from the calculation and does this to an accuracy of about +/- 1 MPH. If you truly were not going that fast then he read another vehicle — not you. He then basically pinned it on you because he thought you looked like you were traveling the fastest of all the vehicles in the RADAR’s range. See… the RADAR has a hugely wide cone that doesn’t just pick up one vehicle but many at once and in both directions. It is set to “fastest vehicle” and the officer tried to figure out by eye which vehicle is traveling the fastest. The problem is that when you are traveling toward the officer he has a very short time to make that determination and it is impossible to do because also the sense of speed is determined by growth in retinal size as you approach him and if he is focused on your vehicle when you go by you get the ticket even though it may have been someone behind you breaking the law… in fact it could be a panel truck 1/4 mile away and not even in his immediate view — he may think you were the only vehicle within range. But large flat surfaces have a very strong reflection. The devices are very flawed and mis-used even by well trained officers.

  • Mrs.Hanna

    That’s nice radar of laser brands pic of here…thanks to share it..

  • Bruce B.

    I have a Rocky Mountain Phantom 7 detector that is very reliable, but I got cited for speeding recently by an officer traveling the opposite direction. My detector did not go off so I assume he was using something not detectable by my device. Any idea what this could be? I believe LIDAR cannot be used from a moving vehicle so must be something else.

  • Sue

    How do you know this information as a matter of fact as a person trained on the two different radar speed indicators … Or by informations out there. I need absolute information on the radar used by highway patrol in alabama I was ticketed for 86 but was not traveling but 65 and as I can in line of sight of the officer I went to get over in the other lane and a vehicle was approaching and sped by quickly and after he passed I pulled in the left lane as I always do when someone is on the side of the road out of courtesy, and as I pass him I am doing 60 and after I pass I move back into the right lane and he comes rushing past with lights on going after the car that passed me and then all of a sudden he comes back out and starts flashing his lights and then out his spot light on us and I’m freaking he comes into my lane pushing me over into the left lane and I see in mjy rear view a big truck coming and I pull over and I’m five car lengths in front of the car he pulled over and the. He approaches the passenger side and said to me are you traveling together and I said no he said do you know how fast you were going I said not exactly but I wasn’t speeding I wasn’t sure of the speed on that highway and I was I. A rental car that didn’t have cruise control so I had to keep watch and I since I didn’t know the speed I was keeping it between 65 to 70 and still didn’t know the speed he never said or maybe I was just so startled by the his early actions of what I felt this officer putting me in harms way and I’m a retired vet, I have been driving 35 years and have never experienced this action. Anyway back to the question he said he clicked me at 86. I went to court and the office didn’t show so the judge reset he said either guilty or reset so I’m not guilty so I reset and I live 700 miles away no consideration at all and the officers corporal knew I was going to court. But the officer supposedly had computer training and couldn’t make it and he is in the same town and when I called to see where he was he was on duty and when I said I thought he had training then the corporal said well he is later and the. Said his car was being updated with a new computer
    So can you give me any substantial evidence I could use in court on Tuesday to support my argument that I was not speeding Thank you and have a blessed day

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