Chicago Judges Not Impressed By Laser Gun Speeding Tickets

Good news if you live in Chicago and enjoy driving too fast: traffic court judges in Cook County are throwing out speeding tickets issued by laser gun-wielding cops because the LIDAR technology is apparently not “scientifically reliable.”

Because there is no state law specifically stating that laser guns are scientifically reliable, a costly and time-intensive hearing is required whenever a defendant challenges the technology.

Not all judges are throwing the tickets out, but as the article points out, defendants who admit and pay their fine by mail can’t get in on the confusion and incompetence.

Although speeding is dangerous and breaking the law is wrong, this must be some nice schadenfreude for residents of a city that tried to make its residents pay 28 quarters for two hours of parking.

Use of Laser Guns to Catch Speeders Is Questioned [Chicago Tribune]
(Photo: Extra Ketchup)


Edit Your Comment

  1. Wang_Chung_Tonight says:

    on a similar note, all officers will be required to plot the cars progression on a bar graph and use physics to calculate the velocity and acceleration.

  2. MightyDwarf56 says:

    Sweet, now they need to tell cops that “Pacing” is not an accurate way to tell if some one is speeding either.

    • nstonep says:

      @MightyDwarf56: Yeah…but it is. If they’re going 65 and you’re pulling away…you’re not going 65.

      • darkforcesjedi says:

        @nstonep: What makes you believe the cop’s spedometer is any more accurate than the civilian’s? At 65 mph they’re only accurate to within 1 or 2 mph.

        • Skipweasel says:

          @darkforcesjedi: Don’t know about US police cars, but TrafPol cars in the UK have different and calibrated speed measuring systems – not just the ordinary car speedo. If you’re nicked you can demand to see the certificate of calibration.

        • MauriceCallidice says:

          @darkforcesjedi: “What makes you believe the cop’s spedometer is any more accurate than the civilian’s? At 65 mph they’re only accurate to within 1 or 2 mph.”

          I can’t speak for other locales, but in Pennsylvania in order for a ticket issued based pacing to be valid the police are required to have had the pace vehicle’s speedometer tested and certified for accuracy within a certain window prior to the issuance of the ticket.

          Requesting a hearing on the ticket before the Magisterial District Judge and asking the police to produce the certificate of accuracy is one way to challenge such a ticket.

        • rte148 says:

          @darkforcesjedi: check out p71 Crown Vic variants’ dash boards on some car selling website. They have a notation stating calibration. Whether or not it really is, well, that’s your row to hoe.

    • ktetch says:

      @MightyDwarf56: If they’re using an accurate (ie recently calibrated) speedo, and using a videotape system that records vehicle speed (either directly, or via GPS) then it’s acceptable. It just has to be over a significant distance (for instance, in the UK, time&distance measurements need a minimum of 1 mile)

  3. qwerty001984 says:

    I don’t get it.
    The gun will have testing records, calibration records, and manufactures specifications.

    What does passing a law have to do with saying something is scientifically reliable?

  4. osiris73 says:

    The last ticket I got years ago was by VASCAR. My laser/radar detector has saved me otherwise. I have to imagine that VASCAR can’t be uber-reliable either. Its only as accurate as the cop is reflexive.

    • djohnston says:


      VASCAR doesn’t transmit anything.

      Visual Average Speed Computer And Recorder

      When the car passes a reference (overpass, telephone pole, etc.) the operator presses a button. When the car passes a second reference mark, the operator presses another button. The VASCAR unit the computes the speed.

      So how did your laser/radar detector save you from this???

  5. downwithmonstercable says:

    It’s interesting they call this not scientifically reliable. They must have super high standards. In Washington, helicopters or airplanes fly above the freeway, eyeball you passing two points and time it with a stopwatch, then do some division and figure out your speed. I’d think the laser would be a bit more accurate than that…

  6. soundreasoning says:

    I actually love this. Time switch over from the Frye standard Illinois. or wait no, keep the Frye standard and don’t progress the laws in line with technology so the public can continue benefiting.

  7. Mackinstyle says:

    LiDAR is very reliable. I work with LiDAR data daily. From 30 000 feet up, we’re getting distances from the platform/sensor to the ground with error of under 10cm.

    • steve6534 says:

      @Mackinstyle: As long as the pieces aren’t moving I agree. I think the argument has more to do with cosine error where the angle of measurement is constantly shifting.

  8. ElizabethD says:

    That battle droid did NOT fire first.

  9. self-check says:

    “Good news if you live in Chicago and enjoy driving above the speed limit

    There, fixed that for you.

    • zumdish says:

      “There, fixed that for you.”

      A couple more you missed: “Although speeding is dangerous and breaking the law is wrong . . .”

      Both are Not Always So.

      Speeding isn’t dangerous, driving dangerously is dangerous. Exceeding the posted speed limit is not in itself dangerous, depending on circumstances, especially with so many limits set artificially low.

      And if it wasn’t for millions of people engaging in civil disobedience for years by breaking the U.S. National Maximum Speed Law we might still have that POS law. Sometimes lawmakers create bad laws and one of the ways they get changed in a democracy is people break them.


  10. Greasy Thumb Guzik says:

    Wrong, wrong, wrong!

    Mark Brown, who started the entire thing wrote yeasterday that the city is again prosecuting speeders on LIDAR tickets!

    “City ends dismissals, goes back to prosecuting ticketed drivers

    November 15, 2009

    BY MARK BROWN Sun-Times Columnist

    They say you can count on there always being somebody who will come along and screw things up for everybody else.

    I’m coming to grips with the fact that, in some circles at least, I may be that somebody.

    As of this past week, there is no longer any automatic free pass in Traffic Court for drivers who have been ticketed for speeding by police officers using LIDAR speed detection equipment.

    The city’s Law Department went back to aggressively prosecuting the cases after my columns the previous week about how all the LIDAR tickets were being dismissed in Chicago’s Traffic Court on the basis of a legal dispute over whether local prosecutors have sufficiently proved that LIDAR is accurate and dependable.”

  11. a5un says:

    It’s about time when someone with a brain recognize this. There’s a huge difference between accuracy and precision. A laser gun can be very precise, but it doesn’t mean it’s accurate. It all depends on how accurately the cop can aim.

  12. henrygates says:

    I have a problem with this. First, I hate people who speed. I always drive the speed limit, and so everyone who speeds pretty much acts like a complete jerk. Tailing me, cutting me off, and I’m always in the right lane! Speeding tickets are costly. Driving 5-10mph over the limit will NOT get you to your destination significantly sooner, especially if you are in city traffic with stop lights/signs. Financially, it makes no sense to speed. Second, when people waste court time fighting their speeding tickets it wastes taxpayer money. Third, I get pretty tired of people passing me by and then slamming on the brakes and going 10mph UNDER the limit because oh noes, a cop is ahead.

    It doesn’t matter what the speed limit is. It could be 100mph, and people will still exceed it. I do not understand.

  13. gavni says:

    Wait, did you just say that if the speed limit is set such that 15% of traffic is speeding that people are not always speeding?

  14. Ronin-Democrat says:

    Well my car is made of highly reflective material to scatter the laser beam.

    Nertz to the fuzz man.

  15. ubermex says:

    @pecan 3.14159265: Most states DID study it and give it the legal go-ahead. It looks like Illinois just slept through that class or something. It IS accurate, they just didn’t do the legwork to get that on paper, so it has to be re-proven in every case.

  16. Cant_stop_the_rock says:

    @pecan 3.14159265:

    It is reliable and accurate, it just hasn’t been tested and proven in court yet. How are they going to prove it in court without using LIDAR to catch any speeders? They have tried to go through the process of proving it in court, but each time they try to do that the defendant suddenly realizes they were guilty.

  17. humphrmi says:

    @pecan 3.14159265: In Chicago, the scientific accuracy of Laser (or any new speed tracking technology) has to be confirmed in its first case by holding a special hearing called a “Frye Hearing”. This is a very expensive hearing that is typically held the first time that a defendant challenges a ticket.

    Well, what happened is that for years, nobody ever challenged the scientific accuracy of LIDAR… they might have challenged other aspects of their ticket, like conditions or such, or maybe asked for “supervision” (a special handling situation where you basically plead guilty, but the ticket is expunged from your record if you keep a clean driving record for about a year).

    So, nobody ever challenged the scientific accuracy of LIDAR, and hence a Frye Hearing was never needed.

    Until someone did challenge it, and that person’s bright attorney realized that a Frye Hearing had never been held. That opened the flood gates – every attorney “in the know” now had a club – threaten a legal challenge, or let my client off. Most judges are too busy to want to go through the process of a Frye Hearing, and their bosses don’t want them to spend the money on the scientific experts anyway.

    So now that it’s been in the news, I guarantee a judge will call for a Frye Hearing for the next person that tries to get out of a ticket that way. This loophole will get closed, now that there’s some sunlight on it.

  18. Papercutninja says:

    @Eyebrows McGee (now with more baby!):

    Yup. Tried that. NYPD Highway Patrol testimony STARTS off with the officer stating on-record that “At 6am on the [morning of the incident] i calibrated unit# XXXX to determine it’s accuracy. ETC ETC.”

    I think that they’re on to our little internet “how to fight a traffic ticket” tips.

  19. TheSpatulaOfLove says:

    @Eyebrows McGee (now with more baby!):

    I want in on this action. I ALWAYS go to court for my driving infractions, but they’re getting shifty here in MI. You don’t see a judge anymore, not even a magistrate. The last ticket I got, I was locked in the room with a sleazebag prosecutor and pretty much threatened to take a plea bargain if I didn’t want ‘the points’. He doubled the fine and rewrote the charge and I was on my way…

    I’d love to beat them at their own game – please tell me more!

  20. NoDavidOnlyZuul says:

    @ubermex: That was up up for sale to the highest bidder, but no one wanted THAT job. I’m from IL so it’s cool.

  21. Blueskylaw says:


    I don’t think they can calibrate the guns themselves, I believe they have to be sent out for this procedure.

    Does anyone know for sure?

  22. brain_grenade says:

    @Papercutninja: The trick isn’t to determine whether or not the unit was calibrated. That part doesn’t concern me. The primary function of this request is to “provide documentation” of it’s calibration by a certified person in a particular time frame.

  23. subtlefrog says:

    @Papercutninja: In Los Angeles, the only person I know who has been to court said he was in a room with an asshole judge and a load of people. He’d gone in with grand plans to fight his ticket, but gave up pretty quickly.

    They were to stand, one at a time, and give their name, citation number (I think it was) and how long it had been since they last attended traffic school (which you can apparently do here to reduce the number of points on your license). One guy said one thing other than this, got screamed at, and was sent to the back of the line.

    The guy I knew got up there and turned name, citation number, and the fact that he’d never been to traffic school all into one big word he strung it together so fast. And was out of there. With traffic school as his penalty.

  24. RandomZero says:

    @MightyDwarf56: I’m genuinely curious as to how that stands up in court. Up here, they require some sort of documentation (recording of their speedo reading or GPS logs, as noted above, or LIDAR logs) or it gets tossed the moment it’s challenged for lack of evidence.

    That said, they do have a nasty habit of illegally hiding their speed traps and lying about that.

  25. orielbean says:

    @MightyDwarf56: If people are oblivious enough to have a cop driving closely behind them to estimate speed, they deserve a ticket. Be mindful of the headlight arrangement of 90% of the cop cars and you will live a ticket-free existence. It doesn’t help against an unmarked cruiser or the speed gun, but riding the left lane is just begging for attention from them.

  26. Sudonum says:

    Yeah, and when I proved to a judge that there was no way I could have been going the speed that the cop said he paced me at he found me “guilty of something over 55 mph”. What a load of crap.

  27. hkellogg says:


    not true NJ state troopers have their speedometers calibrated by an angency and pacing totally sticks in court there is no way to overturn it

  28. Eyebrows McGee (now with double the baby!) says:

    @TheSpatulaOfLove: @Papercutninja: It seems to depend a lot on the local area. My husband once got ticketed for 50 in a 35 … in a 50 speed zone. The cops where we (and my friend) lived were incredibly lazy. My husband brought in pictures of the intersection the ticket listed him being stopped at with the SIGNS RIGHT THERE.

    When he got stopped, the cop was like, “You were going 50 in a 35.” And he was like, “I was going 50 in a 50, the speed limit sign is RIGHT THERE.” And the cop was like, “Sir, I am aware of the speed limit here, AND IT IS THIRTY FIVE, regardless of what that sign might say.”

    So yeah, they didn’t so much ever calibrate their radar guns.

  29. shadowkahn says:

    @RandomZero: Not entirely true. Sometimes you can catch scatter off of other people’s cars. But usually even that only gives you about 1/8 of a second to react and slow down. Not enough time.

    If you must speed, the trick is to get yourself a radar rabbit. Wait till some idiot passes you doing 80, and then follow him. He’ll catch the radar/lidar, and you’ll be long gone when the cop is done with him.

  30. roothorick says:

    @orielbean: Unmarked cruisers are easy to spot too. They’re unfailingly all a certain make and model for a given city (Chevy Impalas here) and have a suspiciously high ground clearance.

    Of course, then there’s the cities that buy european musclecars and stick cops in them…