Quote:
Originally Posted by Por_sha911
In the literal physics sense that is true but, everyone makes a big deal over the fact that Laser has to be aimed at a flat reflective surface like the front bumper or a tag to get a reading. If something with as little light reflection as a dark cloth jacket can do the job then Laser can work on any part of the car. Hence, either the above understanding is false or the vid is bogus.
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Laser will reflect off of just about anything. Hunters use laser range finders all the time to get readings on how far away a game animal is, so that they can accurately place their shots at extended range. They are particularly popular with bow hunters, owing to the looping trajectories of arrows even at close range. But, alas, therein lies the problem...
It is precisely
because laser will reflect off of anything that leads to its inaccuracy in the manner in which police deploy it. It is absolutely imperative that it be reflected off the same surface for all signals that it uses to verify speed. Do some research on laser creep error; there is a plethora of reliable, authoritative information available on this topic.
The simple fact of the matter is that it is humanly impossible to hold a laser gun steadily enough while tracking a moving vehicle with it to ensure that common reflective plane criteria is met. Not at the ranges from which officers are "shooting" at moving vehicles. The claims of accuracy at extended ranges, 500-1500 yards, are patently absurd. If laser truly only reflected from flat, reflective surfaces, they would simply be unable to obtain a reading at the ranges they claim. No one can hold one steadily enough to track a moving license plate or headlight at 500 yards.
Fortunately, they don't have to. As Mike mentioned earlier, the beam itself will disperse over a 2.5 - 3 foot diameter at 500 yards, increasing to 4 feet or so at 1500. So the officer now has a 3 foot diameter circle that, if he is exceptionally steady, will be bouncing willy-nilly all over the front of the target vehicle. After all, we have been told they just aim at the entire front of the car at those distances. So when the unit receives the returning signal, did it get the part that bounced off of the license plate, the headlight, the top of the windshield, the road in front of the vehicle, a splash from a following vehicle, a splash from a vehicle beside it, or what? Neither the laser nor the officer have any way of knowing. The result can be wildly inaccurate readings.
If the officer is conscientious enough, he will use other means to verify that a vehicle is speeding. Unfortunately, many are not. Even more unfortunately, the courts, in their revenue generating zeal, turn a blind eye to these known problems and will take an officer purely on his word that he got a good reading. No evidence required, thank you very much, you can pay at the window on your way out.
I think it is unconscionable that these devices are still in use. They appear to be deployed almost exclusively to try to trump radar detectors. So essentially the powers that be are willing to compromise accuracy and convict innocent motorists in their zeal to possibly catch a few more that may be running detectors. I would venture to guess that far, far more innocent drivers get busted by bad readings than get busted while actually speeding with a detector. They are that inaccurate. The authorities deploying them know this. The courts know this. The manufacturers know this, and knowingly misrepresent their product. And yet they are still in use. That should concern us, here in America.