Speed camera detector

[unknown]

how do speed camera detectors work? i also herd that there was something that blocked speed guns is it true and how do they work?

[sft42]

Firstly, they have to measure your speed. This bit can be done in two ways. One way, by using piezo-electric strips embedded in the road; two such strips at a known distance apart will detect your wheels over them. The time it takes between the two strips gives the speed. (Speed equals distance divided by time.) Another way is to use radar. By emitting suitably high-frequency radio waves, they can bounce these from the vehicle, and the rate-of-change of distance is detected by a frequency shift from the reflection. If this rate-of-change is higher than the rate-of-change for the speed limit, you're caught.

Next, they have to photograph the vehicle. This bit sounds easy but is not so straight-forward. The photographs taken will be both normal and infra-red. (The infra-red will 'see' your registration mark when the vehicle is caked in dirt.) Also, to collect the proof, two photographs are taken in quick succession, so that the distance travelled can be seen. Obviously the "quick succession" is a known time: Again speed can be calculated. To determine the distance, white square marks are usually painted in the gutter of the road and again on the crown of the road. These are a known distance and the two photographs will show the distance travelled.

[unknown]

THANKS but what i ment was the things you buy which tell you when your aproaching a camera

[cupra]

Radar and Laser detectors are simply receivers that warn you if they encounter radar or laser wavelength signals - at the moment it is legal to detect them (...wait for the forthcoming laws that are to outlaw them - coming soon apparently).

To 'jam' the radar or laser guns/installations you flood the area with radar/laser 'noise' that interferes with the detectors (think of trying to hear a lone voice when someone overlays it with 1000 people talking) - but if you try to use a jammer, you'll be breaking quite a few laws....

[unknown]

if you get the tug would they know you were using one. and if you did use one would the gadar gun know it, i mean would it get a false reading or one that gives the impression that a jammer was in use

[cupra]

If you were to Jam a radar GATSO, then you'd probably get away with it. If you jam a handheld unit then the officer using it would no doubt be very suspicious if the unit displays 0mph or the such! Lasers are far harder to avoid because of the narrow cone of light - and there are many other devices that use inductive loops in the road or time/distance to catch you (these are unavoidable!).

[Gef]

Only way to detect a speed camera is by using your eyes! However, the police are pretty helpful by putting up signs, painting them in red and yellow stripes and putting markings on the road! Also, why not just stick to the speed limit?

[BenDToy]

There are also a variety of devices which have the locations of cameras stored in a GPS type system, and so warn you when you are approaching a "known" camera site. They don't actually detect though, and rely on a database being maintained up to date. Gef - must be great to be so law abiding. Most regular drivers would accept that it is possible to inadvertantly exceed the limit from time to time. There is a particular stretch of road near me where the speed limit changes so often that I defy anyone to be sure what the limit is at any given time. Unless of course they are paying more attention to their speed than to driving safely.
The persecution of soft targets continues unchallenged as always.