Laser, the cops point of view
 

This is interesting. It's video from the cops point of view when running laser.

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Very interesting. Maybe something to look into. . .

With about a minute left in the video, we see the world's fastest jogger!

I'm pretty sure that's km/h not mph. :)

Interesting to see how much the crosshairs dance around on the target. As an old shooter, that's the first thing I noticed. The laser targets the license in the first part; the headlight in the last part. From how far away? 1500 meters? Even 500 meters is absurd. Gimme a break. There is no way in hell anyone can hold such a device steady on that size of a target from that distance. It would be damn difficult to hold a heavy benchrest rifle, on sandbags, steady enough to stay on a license plate or headlight at that range. Hell, even with the best target scopes "bumped" to 40+ power it would be difficult to even clearly see a license plate or headlight at that range. And they would have us believe a cop can hold what is essentially a handgun out the window of a car and stay on target at that range? No way.

So why would this even be important, you may ask. They could just target the whole car, right? Well, not exactly. A couple of court cases in Britain exposed the innaccuracies in laser speed measurement introduced through "laser creep". In a nutshell, if the first "hit" is somewhere like the top of the windshield, and the second "hit" on which the laser calculates the speed difference is at the front license plate, it has picked up a greater "distance travelled" by adding that length to its reading. The studies introduced as evidence in those British cases found this can add 15-20 mph to the speed of an average car travelling at 60 mph or so. They found the innaccuracies even worse, for obvious reasons, on "side shots". Imagine taking the first reading on the extreme rear of the car, and the officer's natural shaking making it pan to the front of the car for the second reading. They found at extended distances the wobble of the gun held by an average officer was certainly enough to pan that far down the side of the car between laser impulses.

The laser manufacturers know all of this. The departments using laser know all of this. In the British cases, even when proven to the satifaction of the courts (by a couple of university studies)that these devices are inherently innaccurate, the police determined that with "proper training" they were still effective. And the courts allowed that. Bull*****. It is beyond the realm of human ability to hold one steady enough, and track a moving target smoothly enough to ensure the laser "hits" the target in the same spot. This would be akin to having an officer hit the license plate twice in a row on a moving vehicle at extended range with his sidearm. There is clearly no way in hell any man could ever do that, yet that is the level of steady holding accuracy demanded to make laser reliable.

I find it appalling that these devices are still in use in the face of these credible university studies that so clearly show they are inaccurate. Lasar readings should be inadmissable in any court. The departments that deploy them should, in good conscience, pull them. Yet they remain admissable and in widespread use. I guess a 10-20% error rate, accusing innocent citizens, has become acceptable to both the courts and the departments using laser.

Jeff, those have been EXACTLY my concerns, though I have not seen the administrative details you have. Although I am told the industry refuses to disclose the exact mathematical and functional details of the laser gun's operation, we know that its function is not a 'doppler' function. Rather, as you say, they 'locate' a part on the car twice, and make speed inferences based on the two physical locations. If those two locations are not determined using the same car part (license plate), then the inferences would be indefensible. You'd think. But as you know, the issue is not fairness or evidencial. It is financial. Involving the insurance companies and police departments. With motorists as patsies.

Supe, you were starting to make sense, then you threw out a hair-brained conspiracy theory. :rolleyes:

Laser jammers work (laser detectors do as well but what's the point?). I'm probably going to spring for a jammer soon. More and more lasers in Mich every day it seems like.

police in Holland regulary shoots and books at 500 meters, they have new ones now for 1500 meters
obviously they don't shoot from the hip with those, they use a tripod

Aren't they illegal, though?

X2

No conspiracy. No theory. Fact is, the development and marketing of these technologies is fully and vigorouly underwritten by insurance companies. They invented and developed laser and radar guns, and marketed and sold them to police departments complete with legal defense services. Another fact here is that public agencies rake in the dough from these citations. All this same stuff is true regarding traffic signal cameras also.

Where is the 'theory' here?

Stijn, a tripod is nowhere near steady enough for the precision demanded even at 500 meters, much less 1500. Carrying my shooting analogy a bit further, a master class high power rifle shooter needs to keep his shot dispersion to two minutes of angle or less out to 600 yards to remain competitive. That is within approximately a 12" diameter circle (2 MOA at 600 yards). Not many can do that laying prone on the ground, with all manner of shooting aid (jacket, heavily padded glove on the weak hand, etc.) after years and years of steady practice. No one I know could do that shooting from a standing or sitting position, even with a tripod. Your very heartbeat makes the sights move far more than 2 moa. Now try it with a handgun, with no shooting jacket strapped down tightly to control bodily movement. The natural tremors inherent in all men simply preclude holding that steady. That on a stationary object; it's even more impossible to track the same point on a moving object that accurately at that range.

While already present at 500 meters, another factor comes even more into play at 1500 meters. Mirage. The bending of light rays at that kind of distance can be very surprising. The inaccuracies introduced at that distance are at odds with the level of precision demanded for speed enforcement. And that is only one factor, which in and of itself is enough to render laser inaccurate for precise speed measurement at that range. Add in the inability of a human to hold one, and track with it accurately enough and it simply renders laser useless for the level of precision needed to accurately measure +/- 10-15 mph on a moving vehicle at that range. The manufacturers of, and officials deploying this technology know that. Independant studies have proven that.

You make a lot of accusations there, yet you have nothing to back them up. Sources? Surely you understand the difference between "unfounded accusation" and fact.

Radar jammers are illegal.
Laser jammers are not illegal currently.

The difference is because radio spectrum falls in FCC jurisdiction, while IR spectrum falls into FDA jurisdiction.

Radar jammers are illegal because of federal law having to do with the FCC. Laser Jammers are not affected by the same federal law, but it's my understanding that a few states have put laws in place that make jammers illegal. I think something like "obstructing enforcement of law" or something like that.

I'm pretty sure Illinois has made laser jammers illegal.

Everything's illegal in Illinois...

;)

Thats pretty true...but it's still better than Missouri

Jeff I use laser every day. I write alot of speeding tickets. I don't write chicken**** tickets. I typically don't even start my bike up unless someone is going at least 15 over.

I agree with you about what can happen when the unit is not held steady. It has happened to me. I've never seen a jump of 20 mph, but I have seen it jump 10-15 over. What do I do? I shoot it again. I personally always track the car and get a confirmation on the reading anyway. A properly trained user of the equipment would know that the higher reading was an error, because of the vehicle tracking history and because of the vehicle speed estimation. The difference between you shooting a gun and shooting a laser is that our laser travels at 983,571,056 feet per second and sends hundreds of light pulses a second. At 1500 feet. the spread of the laser is about 21/2 to 3 feet and it never spreads more then five feet even at over 5000 ft. It doesnt need to be held in the exact same place to get an accurate reading. (at distance I go for the entire front of the vehicle)

The courts assume that the people using the equipment are properly trained. I've never lost a case because of my ability or inability to use the equipment.

There are way to many people speeding for me to write someone a ticket who I am not 100% sure was indeed committing the violation.

Hold on. (put on flamesuit) ok. go ahead.