Mobile speed camera lies - LTI 20.20 exposed as unreliable
Published: 15th October 2005
Category: Statistics & Research
Reader's Rage:    [102votes] Experts and two investigations by the BBC's Inside Out programme and The Daily Mail have revealed that the police's favourite speed gun, the LTI 20.20, is flawed and can produce incorrect and unreliable speed readings.
 The device is used in some 3500 speed traps around the UK, but motorists have been prosecuted for speeding when they're adamant that they weren't over the limit. However, the main expert witness called by the CPS to defend the equipment in court is the boss of the UK importer, Frank Garratt, a former police officer and now a millionaire.
In tests the speed gun recorded a wall speeding at 44mph. (Yes, a brick wall, that's not a misprint) Other tests showed a bicycle doing 66mph and a parked car doing 22mph. The Daily Mail reports that even when the camera is set up following the police's own guidelines and the manufacturer's handbook some of the readings were wildly off the mark.
The newspaper wrote "The Mail can expose the scandal of a speed enforcement industry in which the collection of fines is considered paramount - whatever the consequences for innocent drivers caught in police traps by faulty readings." Lawyers told the paper that motorists are now rebelling by refusing to pay fines and fighting their cases through the courts. One solicitor, Barry Culshaw from Southampton, is representing 15 clients who all claim to have been a victim of faulty LTI 20.20 readings.
Another discovery, writes The Daily Mail, is that vital video film, often taken as secondary evidence, is often mysteriously withheld from accused motorists by the CPS. On at least 10 occasions the CPS has suddenly dropped the case against a motorist when ordered by a judge to hand over the revealing footage.
 Dr Michael Clark is Europe's leading expert on laser technology and a former directory of a company making laser detection equipment for traffic lights and car parks. He's also a fierce critic of the speed gun and has acted as an expert witness on behalf of many motorists since he defended himself after being caught for alleged speeding.
Dr Clark says the gun is defective because its wide beam can easily pick up the wrong vehicle and if not held firmly on the target (which is a difficult task itself) it can produce an erroneous speed result because of "slippage".
Reflections from road signs and from other cars, even stationary ones, can also make the laser device misinterpret the true speed of the vehicle. The LTI 20.20 works by sending out a beam to measure the distance of the target from the officer operating it and also how long it takes for the beam to reflect off the target and bounce back. The operator looks through the sights and sees a red dot which he aims onto the target and presses a trigger. Critically the beam must be held firmly at the same point on the moving vehicle. But if slippage occurs and the beam moves up, down, or along the vehicle the gun will measure an inaccurate reading.
In tests in the USA it was shown that if the beam slips from the windscreen of a car down to its grille on the bonnet it can add 8mph onto the vehicle's measured speed. If it slips along the length of the car - which is possible when a vehicle comes around a corner into the speed gun's sights - a whopping 30mph can be added on to the reading.
The BBC's experiments with the LTI 20.20 were dismissed by both the UK importers and ACPO (Association of Chief Police Officers) saying it was impossible for the gun to make any errors and that the BBC used an American version of the gun which they claim has less reliable software.
However, that claim was been rejected by the Daily Mail who obtained a UK version of the gun - a LTI 20.20 Ultralyte certified by Tele-Traffic, the UK importers based in Warwick.
Dr Clark points out during the experiments that the gun uses a multi-mode laser which uses 3 beams, not one. Over a long distance the beams widen so if it's targeted onto one vehicle it can unintentionally hit another vehicle nearby by mistake. Dr Clark said "A policeman can't tell from 400 meters away - or even at a longer distance in many cases - exactly which car he is marking." To demonstrate his point they parked a car at the side of the road and drove a white van past it at just 3mph. The laser gun was pointed at the car from 371 meters away which, according to the handbook, is easily within its capabilities.
As soon as the van drove past the parked car the laser gun picked up the moving van. It was impossible to target just the parked car along and as a result the car was recorded as travelling at 3mph, even though it was really stationary. The experiment was repeated with the van doing 26mph and the gun clocked the parked car at 26mph.
Another problem is reflection from other vehicles. They pointed the gun at a different parked car and slowly drove the white van past. It recorded the parked car doing 22mph. Dr Clark explains "The beam sometimes catches the reflection of a nearby car. It zig-zags to this car before carrying on to the target vehicle and returns by the same route."
In their final experiment they pointed the gun at a brick wall with no moving vehicles in the area. They moved the beam along the wall instead of keeping it perfectly still on a single point to create the slippage effect. The gun was confused and showed a speed of 44mph. Dr Clark said "This shows how a traffic officer can mistakenly pick up a reading from a wall by the side of a motorway or even an empty road if he doesn't target a vehicle properly. Of course there's no record to prove if an officer had targeting the vehicle properly or not. Assumption of accuracy is always taken for granted even if the officer had unwittingly made a mistake.
ACPO state that the gun shouldn't be used at distances more than 500 meters, but Dr Clark says that it's being used in some cases at double that distance.
Despite the recent media interest in these issue the shortcomings of the gun was discovered nearly a decade ago in 1996 in the US state of New Jersey. The state temporarily banned the gun after a court witnessed someone targeting the gun on a wall of the courtroom and it measured 4mph. The lawyer, Joe Maccarone, defending a motorist accused of speeding called on an expert from NASA. The expert said that at just over 300 metres there was only a 60% chance of a human operator hitting a 12 foot wide target with a laser gun. Cars are only 6 foot wide so the chances of hitting something other than the target are very high indeed.
Paul Smith from Safe Speed has demanded that Home Office Type Approval for the device is suspended pending an independent investigation. Speedcameras.org joins Safe Speed in the demand since such high profile claims of inaccurate policing equipment deserve to be fully and independently investigated. The lack of public confidence in the device, and more importantly the fear of being prosecuted and punished for an offence that may not have taken place, is a serious departure from British fair play and justice.
Watch The Video Clip
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Information sourced in part or in full from: Daily MailOur comment: Again the authorities shrug aside the laws of physics and strong evidence in order to continue their charade of ticketing motorists using unreliable equipment and faulty road safety policies. Printer friendly version
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