# Do Radar/Laser Detectors Really Work? **URL:** \ **Category:** Factual Questions\ **Created:** [September 24, 2003, 9:58pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640 "2003-09-24T21:58:09Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Mr.Tattle](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@Mr.Tattle](https://boards.straightdope.com/u/Mr.Tattle)\ **Post date:** [September 24, 2003, 9:58pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/1 "2003-09-24T21:58:09Z")
Not that I would ever condone unsafe driving, but when the law is unjust it is the duty of the just to be unlawful–or something like that. Anyway, I feel like I can drive pretty safely 10-15 mph over the posted 55 mph speed limit on some of the highways I frequent, but have had problems in the past with speeding tickets and am more than a little paranoid about earning another insurance rate hike. There are a number of radar/laser/VG2 detectors available commercially–my question is, do they work? Given my insurance bracket I only need to avoid one ticket for even the pricier models to pay for themselves, but I don’t want to splurge on anything useless. ---
**Author:** ![voltaire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voltaire/32/313_2.png) [@voltaire](https://boards.straightdope.com/u/voltaire)\ **Post date:** [September 24, 2003, 10:07pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/2 "2003-09-24T22:07:57Z")
Yup, they work. Some work better than others though. I would recommend Escort/Passport or Bell brands. From my experience, other brands tend to give off a lot of false alarms. Check out: [http://www.radartest.com/](http://www.radartest.com/) ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 24, 2003, 10:32pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/3 "2003-09-24T22:32:45Z")
Well, not really. Radar detectors are fairly decent, BUT if the police unit is using an instant-on gun type radar, you better hope your detector catches a reflection from a car ahead of you, or you’re done for. Laser detectors are almost completely useless. Yeah, it’ll detect it if it’s aimed at you, but by then you’re already tagged. The beamwidth is much smaller than a radar, and the officer will target either the license plate or one of the lamp clusters and pull the trigger. The amount scattered off a given vehicle is pretty small, and unless you’re close to a targeted vehicle, your detector isn’t going to receive enough to trigger. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [September 24, 2003, 11:29pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/4 "2003-09-24T23:29:24Z")
Radar dector? Two words [Valentine One](http://www.valentine1.com/home.asp) Some of the user stories about Laser dection are somewhat interesting to say the least. ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [September 25, 2003, 1:03am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/5 "2003-09-25T01:03:27Z")
Folks can tell you all they want about how good their detector is, and how it saved them and so on. But unless you’ve actually worked speed traps for a long amount of time, and know how radar guns work, you’ll never now how useless detectors are. A radar detector is only good if: A) the officer has his radar on continueous wave mode (unlikely now days) or B) there are cars ahead of you getting zapped by instant on. If you’re a lone car, or the leader of the pack even a Valentine won’t save you. Laser detector?😛 **Bwaaaaaaahahahahahahahahaha!** 😛 Forget it! The department I used to work for Full-time was the 2nd in the entire state to get a laser gun. When the beam hits the license plate it’s only about the diameter/circumference of a soda can. A laser detector sitting on a dash or visor is pretty much useless. And when the detector does “see” the beam it’s too late : ALL laser guns are ALWAYS instant on. I wish the department I now work for part-time had one. Seeing the look on detectors owners faces when the didn’t get a single beep is priceless!😛 ---
**Author:** ![Mr.Cynical](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@Mr.Cynical](https://boards.straightdope.com/u/Mr.Cynical)\ **Post date:** [September 25, 2003, 1:32am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/6 "2003-09-25T01:32:34Z")
In contrast to the previous user testimony, it appears that there is currently only one laser speed detector that is able to bypass detection/jamming. The Laser Atlanta Stealth Mode laser gun appears to have pulse code modulation, thereby encrypting the laser return, rendering scrambling useless. Additionally, on the radar front, there is a radar speed detector with a 67 millisecond on time that will generate, receive, and measure a radar pulse quickly enough that a “detector detector” hasn’t the chance to even recognize it’s being painted. [Source](http://www.speedlabs.com/) [Cite 1](http://www.k40.com/Dealers/DealerSupport/pdf/SML%20LASERWARS.PDF) [Cite 2](http://www.k40.com/Dealers/DealerSupport/pdf/SML%202003%20TEST.pdf) I grant that the documents provided in cite are from k40 electronics, a manufacturer of defeat products, but the testing and evaluation are from Speed Measurement Labs, and appear valid. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 25, 2003, 1:38am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/7 "2003-09-25T01:38:07Z")
> [@](#): > > \*Originally posted by Mr. Cynical \* > **In contrast to the previous user testimony, it appears that there is currently only one laser speed detector that is able to bypass detection/jamming.** Nobody mentioned jamming. All the previous posts were about _detectors_ and their efficacy. PCM would do nothing to ward off detection. Laser detectors are pretty useless in any case, as I said; your advance warning time is practically nil. ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [September 25, 2003, 2:20am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/8 "2003-09-25T02:20:27Z")
> [@](#): > > \*Originally posted by Mr. Cynical \* > **In contrast to the previous user testimony, it appears that there is currently only one laser speed detector that is able to bypass detection/jamming** Bah. I roll my eyes :rolleyes: at so called jammers. The manufacturers can claim anything they want. I’ve attended a couple of testings of them, and police officers were doing the testing. Most of the jammers were crap (especially ones made by “Rockey Mountain Radar”) and the others that worked, only worked occasionally. And trust me, the day someone makes one that works well, it will be outlawed pretty quick. testing them was a blast, though! Another thing, I do 90% of my radar traps (and when I had a laser gun, laser traps) by clocking the vehicle from behind. I park in between some parked cars or hide under a bridge and wait for the car to pass me. Then I zap them. In the case of laser this means I was zapping the rear license plate. Most of those “laser jammers” are set up for the front plate or bumper. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 25, 2003, 2:28am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/9 "2003-09-25T02:28:04Z")
Incidentally, the [FCC](http://ftp.fcc.gov/Bureaus/Compliance/Orders/1997/fcc97404.txt) has ruled radar jammers to be illegal, despite manufacturer’s claims to the contrary. ---
**Author:** ![tadc](https://avatars.discourse-cdn.com/v4/letter/t/f07891/32.png) [@tadc](https://boards.straightdope.com/u/tadc)\ **Post date:** [September 25, 2003, 4:43am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/10 "2003-09-25T04:43:16Z")
They work, in the sense that they alert you when radar/laser is being used in the area. Whether they work in the sense that they actually keep you from getting a ticket is a different question and entirely dependent on how smart the officer/you are. ---
**Author:** ![Mr.Cynical](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@Mr.Cynical](https://boards.straightdope.com/u/Mr.Cynical)\ **Post date:** [September 25, 2003, 4:46am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/11 "2003-09-25T04:46:52Z")
> [@](#): > > \*Originally posted by pkbites \* > \*\*Bah. I roll my eyes :rolleyes: at so called jammers. The manufacturers can claim anything they want. I’ve attended a couple of testings of them, and police officers were doing the testing. Most of the jammers were crap (especially ones made by “Rockey Mountain Radar”) and the others that worked, only worked occasionally. And trust me, the day someone makes one that works well, it will be outlawed pretty quick. testing them was a blast, though! > > Another thing, I do 90% of my radar traps (and when I had a laser gun, laser traps) by clocking the vehicle from behind. I park in between some parked cars or hide under a bridge and wait for the car to pass me. Then I zap them. > In the case of laser this means I was zapping the rear license plate. Most of those “laser jammers” are set up for the front plate or bumper. \*\* PK- I’m referring to the laser “jammers”, in specific. Additionally, if you take the time to look at the provided link, you will see that Speed Measurement Labs actually contracts and consults with local and state police as well as numerous DOT agencies to provide training to police agencies in the proper use of laser and radar detection systems. I have to look at them as impartial in that they test the evasion systems to see if they actually DO get around detection. I know for certain that the k40 provides rear protection, I worked in an installation shop 🙂 Q.E.D. - Calm down, big guy! I’m addressing more than was asked for. The more I read your rebuttal, the more I don’t understand where on earth you’re coming from, aside from some bizarre quasi-aggressive scaryland. The OP asked for information about radar detectors, I gave information based upon what I know about commercially available high-end models. Of course PCM wouldn’t made a difference whether a motorist could detect that he were being illuminated. A detector is only looking for the radiation, not a specific pattern of it. The PCM, as I referred earlier, is there as a way to defeat returned broadcast IR with incorrect info. PLEASE trust me that I know from where I speak on this, but am too damn tired to elucidate 🙂 And yes, radar jammers are dead on illegal. All of it is mentioned in the SML publications. Cited, sealed, delivered by yours truly, Mr. Cynical - [2A0X1C](http://www.e-publishing.af.mil/pubfiles/af/cfetp/cfetp2a0x1c/cfetp2a0x1c.pdf), [2A5X3C](http://www.e-publishing.af.mil/pubfiles/af/cfetp/cfetp2a5x3c/cfetp2a5x3c.pdf) cut-trained ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 25, 2003, 5:08am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/12 "2003-09-25T05:08:35Z")
> [@](#): > > \*Originally posted by Mr. Cynical \* > **Q.E.D. - > Calm down, big guy! I’m addressing more than was asked for. The more I read your rebuttal, the more I don’t understand where on earth you’re coming from, aside from some bizarre quasi-aggressive scaryland. The OP asked for information about radar detectors, I gave information based upon what I know about commercially available high-end models.** Yes, and I expressed my opinion on both. And most of my posts regarded standealone laser detecting units that had little efficacy. You want to rely on RD units to detect your presence and speed, knock yourself out. ---
**Author:** ![Badge](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Badge](https://boards.straightdope.com/u/Badge)\ **Post date:** [September 25, 2003, 6:59am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/13 "2003-09-25T06:59:42Z")
One more thing: if you have a radar/laser detector visible in your car when you’re stopped, most officers will write you rather than giving you a warning. There are two reasons for this: 1. it indicates that you like to speed and disregard the law, and 2. the detector may have gotten you out of some well-deserved tickets in the past, so you’re getting this one. All in all, I think that they are a bad idea. ---
**Author:** ![Mr.Tattle](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@Mr.Tattle](https://boards.straightdope.com/u/Mr.Tattle)\ **Post date:** [September 25, 2003, 10:32pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/14 "2003-09-25T22:32:51Z")
Thank you all very much for the good input, discussion, and sites. I am going to go ahead with a detector, although it seems pretty clear that my best strategy is to keep my eyes peeled and be sure not to lead packs, but rather follow fast drivers. As far as laser detection goes I’m getting it because it’s included (along with “VG2” detection, or radar detector detector detector), but I don’t expect it to be much help. However, I’m not worried as far as that goes–based on my previous experiences fighting tickets I understand laser clockings are much less likely to hold up in court because they’re less commonly used and more prone to user error (e.g., how can the officer be sure he actually hit the liscense plate and not a rounded surface that could distort the reading?). ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 25, 2003, 10:40pm UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/15 "2003-09-25T22:40:52Z")
> [@](#): > > \*Originally posted by Mr. Tattle \* > \*\*(e.g., how can the officer be sure he actually hit the liscense plate and not a rounded surface that could distort the reading?). \*\* You’re a bit confused here. Any surface that offers sufficient reflection for the laser unit will work fine. Police prefer to target the license plates or the lamp clusters, because both of these things relect light directly back to the source, giving a strong return signal. The speed is measure by comparing the time difference between two signal returns and doing some simple math. Accuracy is affected by the same condition that radar is: by the angle of the laser or radar beam with respect to the direction of travel of the target vehicle. The closer to end-on it is, the more accurate the reading. The closer to being perpendicular to the line of travel, the lower the speed reading will be. In other words, even this source of inaccuracy is to your benefit. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [September 26, 2003, 12:10am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/16 "2003-09-26T00:10:40Z")
> [@](#): > > \*Originally posted by Mr. Cynical \* > \*\*In contrast to the previous user testimony, it appears that there is currently only one laser speed detector that is able to bypass detection/jamming. The Laser Atlanta Stealth Mode laser gun appears to have pulse code modulation, thereby encrypting the laser return, rendering scrambling useless. Additionally, on the radar front, there is a radar speed detector with a 67 millisecond on time that will generate, receive, and measure a radar pulse quickly enough that a “detector detector” hasn’t the chance to even recognize it’s being painted. > > [Source](http://www.speedlabs.com/) > [Cite 1](http://www.k40.com/Dealers/DealerSupport/pdf/SML%20LASERWARS.PDF) > [Cite 2](http://www.k40.com/Dealers/DealerSupport/pdf/SML%202003%20TEST.pdf) > > I grant that the documents provided in cite are from k40 electronics, a manufacturer of defeat products, but the testing and evaluation are from Speed Measurement Labs, and appear valid. \*\* About this from the Valentine one [site](http://www.valentine1.com/pop/) > [@](#): > > Local ticket writers are starting to brag about a new kind of radar; they say it nails radar detector users without warning. > > Yes, in our testing the MPH Industries model BEE IIItm has a POPtm mode in which it’s undetectable. When operated in that mode, it also produces erroneous speed readings every time. > > Moreover, we believe MPH Industries knows this feature is faulty. Why else would it advise, in the accompanying Operation and Service Manual, as follows: > > **“A note of caution: Information derived during the POP burst is non-evidential… Citations should not be issued based solely on information derived from the POP burst.”** > > In actual testing of a BEE III in our laboratory, we quickly learned why MPH Industries is covering itself in the fine print. The POP mode is fundamentally flawed. It consists of a lightning-quick radar burst, over and done with before a radar detector can pick up the signal. We consistently measured the POP duration at 67 milliseconds (that’s 0.067 second). > > Unfortunately for accuracy, that burst is over the speed limit for the BEE III’s own internal components. > … > The POPtm burst works by cold starting the radar’s Gunn oscillator, and its 67 ms duration is shorter than the component’s warm-up time, so the entire POP takes place in a period of frequency transition. The chirp rate is a measure of frequency change per unit time during this POP. We tested the one MPH BEE IIItm available to us and determined the chirp rate of its Gunn oscillator. > > What would be the chirp rate of other BEE IIIs? As a way to create an envelope of possibilities, we tested quite a few Gunn oscillators in our own stock (we buy them for test gear we design for use in our laboratory) and we confirmed that our BEE III sample falls within the range of commercially-produced components available to any manufacturer. Interestingly, we had never tested this parameter before, because it is irrelevant for the steady-state applications intended for these components. > > The best rate (lowest) in our test is -0.0198 Hz/nsec; the worst is -1.069 Hz/nsec. > > **During a POP burst, this frequency change adds (or subtracts, depending upon direction of vehicle travel) to the Doppler shift, causing an error in the speed reading.** > … > For the best Gunn oscillator we’ve tested, the error at 1/2-mile range calculates as follows: 0.02015 Hz/ft multiplied by 2640 ft multiplied by 2 (out and back) divided by 100.803 Hz/mph = 1.1 mph. > > For the worst, 1.087 Hz/ft multiplied by 2640 ft multiplied by 2 (out and back) divided by 100.803 Hz/mph = 56.9 mph. > > The following table shows the radar error for best- and worst-case Gunn oscillators we’ve tested. > > --------- Radar Error --------- > Range :)Best case :eek: Worst case > 500 ft 🙂 0.2mph :eek: 10.8mph > 1/4 mile 🙂 0.5mph :eek: 28.7mph > 1/2 mile 🙂 1.1mph :eek: 56.9mph > 3/4 mile 🙂 1.6mph :eek: 85.4mph > 1 mile :)2.1mph :eek: 113.8mph > 1 1/2 mile :)3.2mph :eek: 170.8mph (bolding mine) And from your 2nd cite > [@](#): > > However this mode may not be used in issuing traffic citations as stated in the MPH Operator’s manual. POP does not allow the officer to meat the legal requirements of locking a speed reading to legally establish a “visual tracking history” and is advised only to be used in areas of suspected high radar dector use. If an officer sees an excessive speed they must trigger the radar gun traditionally to obtain a legally accepted speed. Needless to say when the gun is triggered in traditional mode a good radar dector should pick it up. If the gun is used only in POP mode it does not produce a valid reading that can be used in court. Using this gun in POP mode without using the traditional triggering of the radar gun to obtain a legal speed reading is not speed enforcement, it is pure revenue generation. It sounds to me that somewhere there is going to be a dandy test case where a police department is going to get spanked big time by a properly prepared defense. FTR I have received 3 radar tickets in my life. All three were deserved, and I paid all three. But I do live in California where radar is not as widespread and government does not use it as a revenue generation tool. I also do not own a radar dector. ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [September 26, 2003, 12:49am UTC](https://boards.straightdope.com/t/do-radar-laser-detectors-really-work/203640/17 "2003-09-26T00:49:22Z")
> [@](#): > > \*Originally posted by Mr. Tattle \* > \*\* (e.g., how can the officer be sure he actually hit the liscense plate and not a rounded surface that could distort the reading?). \*\* Your ignorant of how laser guns work. They have a scope on them, pretty much like a rifle scope. There is a red laser dot in the scope that tells the operator EXACTLY what his target is. Laser, in fact, is much more reliable than radar when it comes to clocking the right target. When I had a laser gun I wrote over 70 tickets in under 2 years with it, and not one got tossed out. In those days a lot of people were fighting laser tickets becaue it was so new. Many of those people were confused and pissed that their fuzzbuster didn’t make a sound. Over a third of the people I ticketed with the laser gun fought the ticket, many with a lawyer. Not one won.