Confusing Speedguns!
Discussion
I was talking to my dad earlier today and he said that someone at work had said that if you place a CD in the windscreen of your car (possibly by the tax disc, shiny side facing outwards) That it will confuse the handheld speedguns and the police can't prosecute you for doing it???
It kind of makes sense, I've seen trucks with a row of CD's in the window before but never knew what they were for.
I'm not sure about exactly what type of speed gun it works for.
Is it a myth or does it really work?
Also, Apparently, if you spray hair-spray on your numberplates, they will not show up on GATSO's. Aledgedly....
Anyone know any more?
It kind of makes sense, I've seen trucks with a row of CD's in the window before but never knew what they were for.
I'm not sure about exactly what type of speed gun it works for.
Is it a myth or does it really work?
Also, Apparently, if you spray hair-spray on your numberplates, they will not show up on GATSO's. Aledgedly....
Anyone know any more?
No it dosn't work, neither does sticking a 2p coin in yer mouth before you do a breath test. That was another urban myth that used to be going round, someone did actually try it with me a few years ago, it's lucky first aid training is part of our job, ever tried sucking a 2p coin and blowing down a tube when yer pissed, no he hadn't either thick git nearly choked. Mind you in the current climate no doubt he or his family would blame the cops and then try to sue us.
quote:
if you place a CD in the windscreen of your car (possibly by the tax disc, shiny side facing outwards) That it will confuse the handheld speedguns Is it a myth or does it really work?
I always thought, or was under the impression that the police aimed the hair dryers at your number plate because it is usually the only forward facing vertical surface!!! So if they aimed at your windscreen, (which is where they would have to for a CD inside the windscreen to upset a laser, the signal would bounce off skywards anyway!!!
Stealth aircraft and ships use exactly the same principle, if every surface is angled, the radar/laser will bounce off in a completely different direction! Which is what makes them seemingly undetectable!!
>> Edited by tvradict on Saturday 11th May 17:34
so if they need a flat suface they cant get a bike by laser front or rear as no surface is flat , am i right or wrong , would be nice to know as a tw@t of a copper nearly had me off my bike last year just entering a 30 and had the gun on me before the 30 sign causing me to brake hard and run wide nearly hitting a wall 
i still managed to recover the bike and flick him the bird as i went past ...kin tosser
i still managed to recover the bike and flick him the bird as i went past ...kin tosser quote:
so if they need a flat suface they cant get a bike by laser front or rear as no surface is flat , am i right or wrong , would be nice to know as a tw@t of a copper nearly had me off my bike last year just entering a 30 and had the gun on me before the 30 sign causing me to brake hard and run wide nearly hitting a wall
Why would you worry if it was before the 30 sign, and wouldn't you be slowing down anyway
No, vertical surfaces are not needed. You'd have to be a highly trained marksmen to hit a number plate at 500 or so feet.
This urban myth was allegedly started as joke by a magazine to see how many young drivers they could get to drive around with CDs stuck to their front bumper. It potentially backfired when it was argued that the tracks in the CD could actually disperse a reflected laser beam (assuming it was stuck on the right way round). In practice this is unlikely.
Traffic cops in other forums have said that aiming is done on the general direction of the front number plate as it is usually the single most reflective point. At 500 feet the laser beam will have a spread of around 2 ft diameter so with good aiming you're likely to strike it.
This following information originates from the States is published at Steve Warren's UK Speedtrap site. It shows the impact of the front number plate on detection ranges:
"Lidar range goes as the fourth root of target cross section. This is a very weak function, and so the range for your state probably falls between these extremes of measurement range to the best and worst licence plates measured:
Georgia licence plate, by itself = 2577 ft.
Colorado licence plate, by itself = 1339 ft.
With no plate- detection range of a Mazda RX7 with headlights retracted is around 800 ft.
No plate, and the lights covered - detection range < 500 ft.
The Uniden detector ad claims that:
Uniden detector is good to about 8000 feet.
Lidar guns are effective to about 2000 feet.
Average operating range of police lidar is about 800 feet.
Typical radar ambushes are 600-800 feet because the police must identify the car and make a visual estimate of speed as well. This argument may not apply to lidar with its narrower beam, since the beam itself identifies the car."
Traffic cops in other forums have said that aiming is done on the general direction of the front number plate as it is usually the single most reflective point. At 500 feet the laser beam will have a spread of around 2 ft diameter so with good aiming you're likely to strike it.
This following information originates from the States is published at Steve Warren's UK Speedtrap site. It shows the impact of the front number plate on detection ranges:
"Lidar range goes as the fourth root of target cross section. This is a very weak function, and so the range for your state probably falls between these extremes of measurement range to the best and worst licence plates measured:
Georgia licence plate, by itself = 2577 ft.
Colorado licence plate, by itself = 1339 ft.
With no plate- detection range of a Mazda RX7 with headlights retracted is around 800 ft.
No plate, and the lights covered - detection range < 500 ft.
The Uniden detector ad claims that:
Uniden detector is good to about 8000 feet.
Lidar guns are effective to about 2000 feet.
Average operating range of police lidar is about 800 feet.
Typical radar ambushes are 600-800 feet because the police must identify the car and make a visual estimate of speed as well. This argument may not apply to lidar with its narrower beam, since the beam itself identifies the car."
quote:
Anyone know any more?
The best one, and this hasn't failed me yet, so don't tell every one or they'll try it and then the authorities will be forced to lower the limits further to keep the revenue up.
Quite simply 30 = 30
40 = 40
50 = 50
NSL = ??
Yes use Gatso's and Portables just keep them off bl**dy NSL roads.
Harry
good point Harry. It's a generally accepted rule that NSL is open to some interpretation - unfortunately some of the boys in blue have been hiding gatso units in bushes, on NSL road in Essex. Not vey nice, to be exercising ones motor at about 75-85mph, and get a double flash. Bear in mind, a) this wasn't me, and b) the road in question has NO junctions, and was dry.. sounds a bit like revenue grabbing?
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