Before speed cameras, the number of road deaths was falling dramatically but this is no longer the case. So do speed cameras really make our roads safer?
By Simon Cox
Presenter, The Investigation
On a chilly morning in west London, a gaggle of schoolchildren dress up in sunflower T-shirts as part of a bizarre publicity offensive for speed cameras.
The group that runs cameras in the capital, the London Safety Camera Partnership (LSCP) is handing out sunflower seeds to every primary school in the capital to celebrate the 1,500 people who have been saved from death and serious injury by speed cameras in the past five years.
The communications manager for the LSCP, Christine Fitzgerald, is adamant they work. "They do save lives - our data suggests a 50% reduction. When you see a camera, just think somebody has either died there or suffered a life-changing injury."
Hundreds of thousands of drivers are not being prosecuted
What does she mean by "life-changing injury"? In London it's applied to anyone who has a serious injury, which can mean everything from paralysis to a broken bone or a concussion. A broken arm is serious, but is it really life changing?
This semantic sleight of hand infuriates the small band of speed camera opponents. Chief among them is Paul Smith, whose group, Safe Speed, does all it can to discredit cameras.
"The figure of 1,500 is a fraud, the vast majority is due to random variation in the location of accidents," he says.
For years the myth persisted that cameras were put up as a way to generate money rather than to make the roads safer.
Earlier this year the Department for Transport (DfT) tried to put this to bed. They revealed the requirements that cameras have to meet before they are installed. Principally, there have to have been three serious injuries at a camera site in a three-year period. In London it's even tougher with four injuries over the same period.
The government say there's compelling evidence to show that speed cameras save lives. The last evaluation in 2005 claimed there had been over 40% less people killed or seriously injured at camera sites.
Dr Linda Mountain, an engineering academic from the University of Liverpool isn't convinced by these statistics. She has spent three years investigating an effect which blows a hole in the government's statistics on speed cameras. It's a statistical phenomenon known as "regression to mean".
Speed camera sites are chosen from accident statistics
In simple English, it refers to the fact that any extreme score - high or low - at one point in time will probably be less extreme the next time it's tested for purely statistical reasons. This is because scores always involve a little bit of randomness - which can go for or against you.
When applied to accident road safety, it's the idea that if nothing was done at an accident hotspot, the number of accidents might fall naturally anyway, with or without a speed camera. Basically, if you are at the top of a list of accident hotspots, there's only way to go and that's down.
Dr Mountain tried to factor this into the government statistics. Her figures were significantly different to the official ones. She found by including "regression to mean", the number of people killed or seriously injured at camera sites fell by just over 20%, half the government's estimate.
Her report was tucked away in an appendix in the last major evaluation, although the government does accept that "regression to mean" has a significant effect.
This isn't the only doubt over road safety figures. The official statistics lump together deaths and serious injuries on the roads. These have shown a significant fall since speed cameras were introduced, leading to the inevitable conclusion - speed cameras save lives.
But the dramatic fall in serious injuries in road crashes puzzled some academics, who didn't think it reflected what was going on in hospitals. So they compared the hospital statistics for road injuries to the police figures, which the government uses.
"What we found was no substantial decline at all," says Michael Goldacre, a professor in Public Health from Oxford University, and part of the research team.
There's an even bigger problem with road deaths. In the decade before speed cameras came in, the number of road deaths fell by over a quarter. In the decade after they were introduced, deaths went down by just 8%, despite the improvement in new cars and the advances in emergency medical care.
The end of decades of rapid improvement is worrying experts like Jeremy Broughton, of the Transport Research Laboratory, who has written a report for the government examining what's happening to the road death figures.
He believes the problem is a minority of dangerous drivers who are not being deterred by speed cameras and need to be dealt with by more traditional forms of policing.
"When you drive home this evening, the likelihood of seeing a traffic cop is actually quite low and it's certainly much lower than it was 10 years ago," he says.
The other problem with speed cameras is they rely on drivers to be honest enough to register their cars properly. We've uncovered evidence that drivers are deliberately registering their cars at other addresses to make it difficult for the authorities.
The anti-speed camera vigilante, Captain Gatso, told The Investigation that he registered his car at a different address, allowing him to ignore any penalties incurred.
Some drivers use false addresses when registering vehicles
It is difficult to say how many drivers are taking measure to avoid speeding penalties but there is certainly a particular enforcement problem in London, where over half of offending drivers are not being prosecuted.
Kevin Delaney, the former head of the Met's traffic police, believes this is evidence of a wider problem that speed cameras can only catch people that are basically law abiding.
"Any form of remote detection such as speed cameras relies on the information supplied by the public. If that isn't correct, then remote detection immediately falls flat. You need traffic police to catch the problem drivers."
The Investigation was broadcast on BBC Radio 4 on Thursday 19 April at 2000 BST.
Below is a selection of your comments.
Speed cameras are only placed in accident black spots because it is cheaper than fixing the underlying problem that causes the blackspot. I live very close to the A14 and most of the accident blackspots are there because slip roads are too short at busy junctions. Most of the accidents seem to happen at busy times where it is impossible to speed due to the sheer amount of traffic. I think it would be far more effective to just put up a sign that says "caution, accident black spot ahead".
Steve Price, Newmarket, Suffolk
The biggest killer is drivers' lack of risk awareness. Cars have developed in safety terms, in all components except the nut behind the wheel. "Risk homeostasis" means that drivers absorb the safety benefits by driving too fast for the conditions, or too close. Instead of improving, the level of risk is maintained, while the consequences of an accident potentially increase. Even 29 mph in a side street may be within the limit but too fast. We need a shift in attitude towards life-long improvements in driving standards - ongoing training and evaluation. Some may find that intrusive, but when it's their loved ones dribbling out of a feeding tube, they may wish more was done by everybody who wants a continued privilege to drive. More visible police on the roads. More spot checks to check registration and therefore accountability. And speed cameras? They mostly take away our focus from where it should be.
Jon M, Stockport, Cheshire
On all speed cameras there should be a speed limit clearly displayed, as I have seen these cameras in max 60mph areas without any max speed showing and witnessed motorists braking hard to 30mph because they do not know if the speed has been reduced here, almost causing a multiple pile up. And that's supposed to help road safety?
David, Hitchin Herts
Your report didn't mention one other factor, in addition to "regression to mean", on the government's figures - of the 3/4 accidents needed at a camera site, none of them have to have anything to do with speed, and include pedestrians falling off bridges, cyclists falling off their bikes, a man being injured by a deer he hit, and other things that have very little to do with cars, let alone fast driving.
Edmund Newman, Lyndhusrt, Hampshire
It still baffles me how people can get caught speeding in the UK? You have warning signs long before the camera finally appears, all big and yellow, how can you not see it? Whereas in Germany the police hide in unmarked cars, behind bushes or curves or even disguise the radar trap as an empty traffic sign. And as to whether speed cameras save reduce accidents... well, I still think it's a great way to make money for the government.
Franziska, Sevenoaks, UK
I wrote to my MP suggesting an alternative to the current speed camera set up. My idea was to have cameras which took photographs of cars travelling at or below the speed limit. Those which did would be entered into a draw and each day a winner would be selected for a prize. Each camera would be sponsored by a major company, who would pay for the camera and supply the prize. (Vehicles would be limited to say three entries a day at the same camera to avoid bottlenecks from people travelling past them all day to get multiple entries). The idea would also encourage people to register their cars properly. I received a reply bluntly stating that the existing laws were enough, and people should not need encouragement to keep within the speed limit. But surely the point is to stop people speeding and save lives.
Allister Clark, London
Speed cameras are completely useless. Deliberate speeders and reckless drivers just slow down for them, then speed up again. They arm themselves with camera detectors and drive around ignoring speed limits with impunity. The only people cameras catch are people who accidentally stray over the speed limit, or, because they are unfamiliar with the area and due to often inadequate signs, think the limit is greater. The other problem with this reliance on cameras is that they don't catch people committing more dangerous acts than speeding (mobile phone use, tailgating, drunk driving, unsafe vehicles, etc)
Andy B, Newport