Mobile Camera Speeding Offence "Rolling Footage"

Warwick_Hunt

DoaM wrote: »

IF the SCP send you the video of the incident AND it shows the cross-hairs AND this shows the target varying THEN you might have a chance of challenging it and winning. *

If not then take the SAC and be done with it. No points and minimal hassle. Fair? No, but it's the pragmatic approach.

* I recall a fairly recent media article or forum thread where someone was accused of speeding but was able to prove human error on the part of the camera operator. I can't find it right now though.

But he needs to be reminded that to get the footage, he needs to turn down the course, reject any fixed penalty notice, be charged to court and enter a not guilty plea.

facade

What the OP originally wanted to know was how the laser speed gun works.

The gun sends a very short pulse of infra red light straight out the front. It reflects back off a flat surface straight back to the gun.
It measures the time for the pulse to go there & back, and works out the target distance.
It does this around 1000 times a second, so it can deduce the speed of the target by the rate of change of distance, over about 1/3 of a second, which gives very good accuracy.

The cone of light is very small, and unlikely to be coming off another vehicle, the evidential footage will show where the beam was aimed and whether or not a speeding hawk dived through the beam, or if the beam flicked from car to car.

The cosine slippage Manxman in Exile refers to is caused by the car moving at an angle to the beam. This works in the car's favour as the distance is measured to the gun, so the greater the angle between the beam and the direction of the car the less the distance to the gun reduces. (If the car travels at 90 degrees to the beam, it wont ever get any closer to the gun, and the measured speed would be zero)

I don't know how the OP's cruise control works, but all the ones I've had will allow you to overspeed on a downhill, as they didn't use the brakes: the cameras are sighted at the bottom of hills as cars accelerate down them unless the driver is using the brakes. So it is possible that the OP was caught at a momentary overspeed that beat the cruise control, due to the spot-on placement of the camera.


Bottom line is try over at pepipoo.

The idea of confusedly asking them to review their footage, as you are sure you were below 30 due to cruise control is a good one, as if they have made a mistake they would surely drop the charge.

However, speeding is an absolute offence: you either were travelling at greater than 30.0000000000000000 mph or you weren't (there is no question of intent). Forget any defence about your inaccurate speedo or faulty cruise control.

brianposter

What seems to be missing from the comments is an appreciation that two independent pieces of evidence should normally trump any single piece of evidence, however well calibrated the single piece of evidence may be.
Infallible systems have so often proved to be flawed that there really should be no argument.

Car_54

brianposter wrote: »

What seems to be missing from the comments is an appreciation that two independent pieces of evidence should normally trump any single piece of evidence, however well calibrated the single piece of evidence may be.
Infallible systems have so often proved to be flawed that there really should be no argument.

Can you point to any source for that particular piece of wisdom?

AdrianC

[quote=[Deleted User];73090175]Can you point to any source for that particular piece of wisdom?[/QUOTE]
Obvious, innit?

An unidentified "tracking system" plus some footage from a cheap Chinese dashcam trump a trained operator using a calibrated, type-approved laser speed camera, any day of the week.

Expert witnesses? The British public are tired of experts!

esmerobbo

Once had a driver go to court with Tachograph (a calibrated device) and tracker evidence, he didn't do too well larger fine and 3 points plus a unpaid day off and brought to my notice that he was off route which cost him a bo11ocking!

Nilrem

brianposter wrote: »

What seems to be missing from the comments is an appreciation that two independent pieces of evidence should normally trump any single piece of evidence, however well calibrated the single piece of evidence may be.
Infallible systems have so often proved to be flawed that there really should be no argument.

Dashcam's don't necessarily show the moment that the speed gun caught him in a way that makes it easy/possible to work out the speed from distance travelled.

And any GPS reading from a consumer device* is the average speed between the last X reading's it's processed from the satellites (accuracy to within X meters), on cheaper devices that can be quite a lag (next time you come to a complete stop in traffic suddenly watch your sat nav display, it can show you moving after the handbrake is applied).

On cops side they've got a scientific instrument with a high level of redundancy/fail safe that is taking hundreds of measurements a second to give a reading (and if any two of those measurements are out of what it'll give an error).


*As they can be affected a change in direction/level of travel.

Manxman_in_exile

Hopefully OP will shortly update on the evidence they receive from CSP.

bartelbe

You can't beat a van equipped with laser equipment by slowing down when you see it. Which lets be honest, is what probably happened.

By the time you see it, too late. Simple rule, if it is an area with camera vans, assume it there and keep below the speed limit.

DoaM

bartelbe wrote: »

You can't beat a van equipped with laser equipment by slowing down when you see it. Which lets be honest, is what probably happened.

By the time you see it, too late. Simple rule, if it is an area with camera vans, assume it there and keep below the speed limit.

Fixed that for you.