Perhaps of more interest is the article in the Mail about the laser speed gun LTI 20:20 isn't as accurate as the Police would have you believe.
They've shown:
Parked cars doing 22mph
A bicycle at 66mph
Moving the laser along a wall gave an indicated speed of 44mph (now that could make for some interesting insurance claims).
Also, the expert witness used by the CPS to convict motorists in these cases is a former police officer by the name of Frank Garratt who, by a strange coincidence, also happens to be the main importer of the laser gauns.
Apparentlty, the laser must be held one one point on the car - usually the number plate. Any movement of the beam can add to the speed reading. Tests in the US have shown that if the beam moves from the windsceen to the grille, it can add 8mph. If it slips the entire length of the car (i.e. as it comes around a corner), it can add 30mph to the reading.
It appears that the device is prone to reading the speed of other vehicles, not just the one it's pointing at, and reflections can confuse it.
Should make life interesting.....
Andy
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A fairly obvious way to get an erroneous reading would be to point the laser at the top part of the rotating wheel.
At the ground, the wheel contact patch is nearly stationary with respect to the road, at hub height, the wheel moves with the speed of the car, at the top of the wheel, you will get a reading almost double the speed of the car!
Number_Cruncher
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I was caught by a Lastec Local Video System,with a LTI 20-20 Laser Device.
I remember being in a queue of trffic following a cattle lorry, i saw the motorbike policeman pointing his speed gun at us and looking at my speedo which was showing 40 mph.
Now 5 months later i have received summons for a magistrates court hearing.
I was sent paperwork offering 3 points and a £60 fine , but as i was not breaking the law I have chosen to fight this (no where on the form was there anything telling what to do if you want to challenge the fine.
I have looked on the internet and cannot help noticing that although approved by the Home Office, the LTI 20-20 is not without its critics.
I have found evidence from America and Israel disputing the cameras worth, but have also found that the Home Office considers it good enough and that is that.
Some German engineers took one of these cameras apart and found that there are three beams side by side which causes doubt on what actually is being tracked.
The photo evidence supplied with the summons shows cross hairs, presuming that the centre of these cross hairs is the actual point the laser was reading, then the point is on the front axle tube (the vehicle is a 1983 Range Rover) and not the number plate as it is supposed to be,meaning that it was measuring a curved surface which would cause an incorrect reading .
A silly question , but is it wise to point lasers at people ?.
I would appreciate any help.
Glen
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Hi Bedfordrl
Best of luck in you fight, there is a growing body of evidence both in the media (Newspapers, BBC Programmes) and on the web to suggest the accuracy of the LI20/20 and the Prolaser3 (basically the same camera but a different manufacturer)is prone to error.
Can I suggest you take a look at Pepipoo.com if you have not already done so as there many success stories on there from those that have chosen to fight convictions for speeding when equipment has been proved to be inaccurate or used in error.
Its odd that the Scamera partnerships require you to confess to a crime without a caution being given or without stating how you may contest their accusation of guilt.
Best of luck
as always
Mark
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"Frank Garratt"
The same, I believe, who when challenged about the ability of the camera to maintain its target on a moving vehicle (the gun measures distance only) said that it was designed to anticipate the new position(s) as the vehicle passed, ignoring the fact that to know this, it would have to know the thing that it was trying to measure in advance!
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It would be so much easier if the SCP automatically released the session video with your car on it or at least had the nouse to check it to make sure the conviction would stand. It is wasting court's time for all these cases to go before the Mags when the people bringing the prosecutions are not making the effort to make sure their evidence is accurate.
I also notice that in Ladyman's (Transport Minister) speech recently was going on about convincing pro motorist groups that road safety was working. This is a 3 year plan. Typical New Lab idea of just spinning rubbish rather than actually spending 3 years discovering what would help road safety improve.
Now the dodgyscope has been on the front of the Daily Mail it's not going to stand up in a court of law for very much longer. The dogyscope is only supposed to be used when the instrument is directly ahead of the path of the oncoming or receding cars. It shouldn't be used at any angle to the road so only enforcement from bridges or middle of roundabouts is technically accurate.
teabelly
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cross hairs
What ensures the laser beam is always pointing at the same place as is indicated by the cross hairs?
There must be an alignment procedure involving a target that can be placed somewhere that indicates where the beam is actually pointing. So you need to be assured that the equipment set-up is in calibration.
Has it been knocked?
What are the posibilities for the beam bouncing back from the front of your 'measured' vehicle onto the front of a vehicle approaching you, on the other side of the road, and back the same way and thus adding the speed of those two vehicles together? No need for the beam to be moved during measurement for that one.
That sort of thing does happen on rare occasions with radar. Similarly if you reverse both vehicle directions and think about backs of vehicles.
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Dont overlook the fact that Scameraships are supposed to be "self financing". Its not in their interests to use equipment that is accurate or to train their operators to use it correctly. They can only exist if they keep on printing NIPs which get paid.
The number of those "caught" speeding that just accept the NIP and pay up is far greater than those who look to see if there is actually evidence of speeding and that the evidence is accurate. The scammers only get to keep the cash if you pay up without question, going to court to challenge their claim you are guilty means the cash goes elsewhere.
Watching the BBC programme was quite frightening you can get the camera to give speed readings for inanimate objects without any bother.
Just what you need when as an operator your job may depend opn the mumber of tickets you can issue in a shift.
As always
Mark
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Looking again at the photo provided, i was coming around a corner and i can see down the side of the Range Rover, so not square on then.
I will try not to quote from the BBC programme as i am sure enough people have already done this to no avail.
What does bother me is that the onus is on drivers to slow down and to penalise them for driving at higher than the set limit but there seems to be no education for the pedestrians to be road aware, remember Tufty and the Green Cross Code Man ?.
I drive for Royal Mail and very very regulary have to avoid kids on bicycles who have no road sense, they come straight out of juntions without looking and i have met lots cycling up the wrong side of the road.
It also bothers me that the roadside camera brigade will actually lie to defend the cameras, i have never understood how taking a photo of someones car then much later sending them a summons can actually avoid an accident.
I have heard it stated that at some speed camera sites the accident rate has gone up, is this true?, and if it is ,then if it is not for the revenue why do why do the police persist with these cameras ?.
Glen
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Glen,
I would strongly advise that you take Mark's advice and take a look (preferably register and post!) on PePiPoo. Sit down with a brew, and take a few hours to read the stuff. You'll be amazed.
If you think it's unjust then see what the guys over there say. Hundreds have appealed and "got off". A surprising amount have had the case dropped and and even more worrying number have been able to prove they weren't actually speeding!
If you want a copy of that BBC segment on the gun, I can email it to you but I think it's nestled somewhere on the PePiPoo site anyway.
Good Luck
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I have taken all your advice and joined up with PePiPoo, and yes I am amazed.
I feel better armed to fight now I know more, it is just a shame that everyone else who feels that the summons is unjust does not fight back as well,some people prefer a quite life,at their expense.
I also downloaded UK driving secrets, the one that is advertised in the car mags,and had a few surprises out of that as well.
Glen
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"I also downloaded UK driving secrets"
How do you rate it? I can't decide whether it's genuinely useful or mostly hot air, but just because I don't like the advertising doesn't mean it's no good...
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"It shouldn't be used at any angle to the road"
And there I was assuming it was smart enough to do the necessary triginometry! Of course, to take angles into account, it would have to know both its own compass bearing and that of the vehicle, which could well be itself at an angle to the road (especially if a motorbike). If it doesn't (as you imply) then the whole thing is hopelessly imprecise...
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Also, from what I've picked up over on PePiPoo, it was suggested (no idea if true) that the owner of the the company, one suggested that on uneven surfaces such as a bike's headlamp, the damn thing predicted the speed or something equally as unbelievable.
All I know for sure is on that BBC interview, he looked very uncomfortable when questioned.
It worries me how it's banned in a number of American states and I think in parts of Canada now too (could be wrong on that one).
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JBJ "It shouldn't be used at any angle to the road"
Ah, but if it is used at an angle to the road, it will record a lower speed than the speed you are actually doing.
(The speed recorded will be = (actual speed) * (cos(the angle to the road)))
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