Effectiveness of speed cameras in preventing road traffic collisions and related casualties: systematic review
BMJ 2005; 330 doi: https://doi.org/10.1136/bmj.38324.646574.AE (Published 10 February 2005) Cite this as: BMJ 2005;330:331All rapid responses
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Competing interests: Member of the Association of British Drivers
Competing interests: No competing interests
Dear Sir,
I would like to agree with andrew Montgomery who said:
>>>>
What if drug companies were permitted to launch their products based upon "relatively poor evidence" and on "studies" without "satisfactory comparison groups or adequate control for potential confounders" ??
It is a fact that many drugs have been launched following thorough double blind case control studies and that these same drugs have subsequently been found to be harmful.
I find it bizarre that an otherwise excellent journal should print such nonsense.
<<<<<
I'd like to go two steps further.
Neither my husband or myself have ever had a speeding ticket or been "caught" by a speed camera.
However recently, we were rung by the Police who wished to talk to us about complaints they had received from two members of the public from mobile phones.
It seems that on a journey from Thames back home, while studiously observing the speed limit, we were a major source of road rage for certain people who live to get between A and B at speeds exceeding those "allowed".
The only parts of the road where we did not experience the fronts of cars up our rear end, were areas notorious for the placement of mobile speed cameras.
The officer politely told that we should be driving in a manner so as not to inconvenience the majority on the road.
Given that we were possibly the only car adhering to the specified limit, we pointed out the "contradiction" of such advice to the officer concerned, who didn't really know what to say.
Then, this week, our son, on his way home from a specialist appointment was pulled over by an officer. Yes, he drives a black, sleek, potentially fast, low slung "batty", so stands out like a sore thumb, and probably catches the eye of those who look out for frothing boy-racers.
At the time he was first tailed by the officer he was being overtaken by many other vehicles on the road. He was issued a ticket for doing 113 km an hour on a 100 km stretch, while all others around him sailed on at greater speeds with impunity.
Had he been driving our old bomb, the only thing he might have been pulled over for, would have been a warrant check.
The fact is that speed cameras don't contribute to anything by revenue collection.
The real problem is people's attitudes to driving, and,.... in our son's case, officers' preconceived ideas about models of cars, and their occupants, while ignoring more worthy recipients of the police's attention.
Hilary Butler.
Competing interests: None declared
Competing interests: No competing interests
Here we have a report advocating speed cameras and lower speeds as an aid to physical casualty reduction. Let us consider the mental health aspect.
Some of my local cameras now trigger at 32mph, as confirmed to me by a magistrate who fell foul of a camera on a three lane dual carriageway in an industrial area with few pedestrians.
Government tells us that fines are expected to rise to five million per annum, then remain at that level. So, it is not expected that cameras will change driver attitudes.
I defy any driver to truthfully claim that he or she does not exceed a limit by a small margin on every journey.
Therefore, if we introduce more cameras, virtually every driver is in danger of being caught and penalised. The potential for huge numbers of banned drivers is real.
In the case of those who must drive to earn a living, the risk to their mental wellbeing is considerable. Loss of licence can lead to loss of employment, loss of house and family breakdown.
And for what? Being caught travelling at 32mph four times in three years? This is a ludicrous notion.
Another health aspect of lower speeds is that of concentration loss. Since the introduction of speed limiters in heavy goods vehicles, the soporific effect of attaining, and holding, a particular speed has led to more crashes as drivers fall asleep at the wheel. I used to drive in pre speed limit times. Traffic was light and I travelled the length of the M1 legally at speeds in excess of 100mph. I never lost concentration. I never felt the onset of drowsiness. Now restricted to 70mph, the opposite is true when the road is clear.
We have one of the best road safety records in the world, but one that has deteriorated since the introduction of speed cameras, for which I can find no other explanation. Indeed, figures published by the Royal Society for the Prevention of Accidents tell us that more people die in domestic accidents than die on our roads.
The report quotes worldwide casualty figures. I would suggest that corrupt countries with poor discipline make a major contribution to those figures. Here, cameras are irrelevant as basic safety attitudes are absent.
In conclusion, I would suggest that no claim for the effectiveness of speed cameras can be upheld in the light of Government's admission, via Alistair Darling, that 743 camera sites saw, “casualties increase rather than decrease” and many others saw no change.
Competing interests: None declared
Competing interests: No competing interests
The authors state that
"Existing research consistently shows that speed cameras are an effective intervention in reducing road traffic collisions and related casualties. The level of evidence is relatively poor, however, as most studies did not have satisfactory comparison groups or adequate control for potential confounders".
What if drug companies were permitted to launch their products based upon "relatively poor evidence" and on "studies" without "satisfactory comparison groups or adequate control for potential confounders" ??
It is a fact that many drugs have been launched following thorough double blind case control studies and that these same drugs have subsequently been found to be harmful.
I find it bizarre that an otherwise excellent journal should print such nonsense.
Competing interests: None declared
Competing interests: No competing interests
Dr Pilkington has been unable to provide convincing evidence of the effectiveness of speed cameras yet is advocating more research. We have had speed cameras in use in the UK for over a decade and yet still cannot establish a causal link between cameras and road deaths. It is time to move on from this failed policy and the tired mantra that "Speed Kills" and to press for a better standard of driving. An improved driving test with retesting at intervals would cost money , but would save lives.
Competing interests: None declared
Competing interests: No competing interests
In response to Paul Smith's insinuation, I can confirm that I do not, and never have had any commercial interests in speed cameras. As a public health professional my overriding concern was to ensure that the best possible evidence around speed camera effectiveness is made available to the public and policy makers. I hope my co-author and I have achieved this aim.
Best wishes,
Paul Pilkington
Competing interests: None declared
Competing interests: No competing interests
It is a great shame that Paul Pilkington did not reveal his prior opinions nor declare an apparent commercial interest[1].
Given his prejudice, it is extremely worrying that he could find no truly substantial evidence of casualty reductions at speed camera sites.
But even if we had excellent evidence of casualty reduction at speed camera sites that would be insufficient to justify the use of speed cameras without also considering effects on drivers across the entire road network.
This is a well known problem. Another paper [2] contains the following warning: "Consider system effects. Injury prevention measures may have effects beyond the individual actions they influence directly. These effects may be harmful or helpful. Always consider potential system effects."
I am absolutely certain that there are very important and substantial negative "system effects" relating to speed cameras. I have studied how drivers routinely avoid road crashes for 20 years and the four critical factors are undoubtedly: concentration, observation, anticipation and attitude. Speed in excess of a speed limit is never a critical factor unless there is also a shortfall in the critical 4. By and large, drivers make responsible speed choices to the point where causing an injury collision is a once in 150 year experience for the average licenced driver.[3]
It is sometimes argued that speed reductions will serve to reduce the severity of "inevitable" impacts. However, real world average impact speeds are far lower than the free travelling speeds that might be effected by speed limits and speed cameras. This is partly because crashes can only take place where there are road hazards and successful drivers routinely slow down where hazards are present.
Even after a serious driver error, there is usually time to brake before impact. The effectiveness of braking before impact is most affected by the instant of recognition of the problem, and far less affected by a speed chosen by a responsible driver. In fact speed choice sets the absolute maximum impact speed, while the moment of recognition often enables a crash to be avoided completely. The average is between these two extremes and is far more affected by changes in the moment of recognition than changes in free travelling speeds.
The bad news for proponents of speed cameras is that, in practice, they undermine 2 of the 4 critical factors in routine crash avoidance.
Observation is undermined because speed cameras encourage much more frequent speedo checking (while an experienced driver does not need to check his speedo at all to drive safely.)
Attitudes are undermined because speed cameras are threatening to drivers. We can see one example of a serious attitude effect in the under- researched "race away" crashes described by Chief Constable Richard Brunstrom in a Times article[4]. He said: "We have a particular problem with motorcyclists slowing down for the cameras but then speeding up and dying on the next corner."
Another attitude problem is that many drivers may be deluded into considering that a speed choice 'must be safe' because it meets legal requirements. Nothing could be further from the truth - 30mph is potentially a deadly speed.
If we were eventually successful at reducing speeds generally the essential process of acquiring driving experience would be adversely affected. [5] Driving experience is closely related to the key component anticipation and also affects concentration and observation skills.
The speed camera debate is vast and is far too frequently undermined by oversimplified thinking. It is only when drivers' thought processes and routine accident avoidance strategies are carefully considered that the complete bankruptcy of the technology emerges.
<ends>
[1] http://ip.bmjjournals.com/cgi/content/full/9/4/293 and
http://bmj.bmjjournals.com/cgi/content/full/324/7346/1153/a and
http://bcc.gn.apc.org/tbc/2002/winter/speedcams.html
[2] http://ip.bmjjournals.com/cgi/content/full/6/2/82
[3] 32million licenced drivers / 214,000 injury crashes in 2003 (source DfT)
[4] http://www.timesonline.co.uk/article/0,,2-1215962,00.html
[5] http://www.safespeed.org.uk/problem2.html
Competing interests: Founder of the Safe Speed road safety campaign.
Competing interests: No competing interests
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A better use of technology
Sir
Fewer cars on the road, better standards of driving by all, requalification at regular intervals, intelligent setting of limits and thoughtful application of the law would all help.
Until this improbable combination of circumstances arises:
In even the most humble of modern vehicles it is genuinely difficult to creep along at thirty miles per hour for extended periods of time. I would welcome the provision of a finger tip toggle switch to adjust a voluntary speed limiter in five mph increments up or down. Then I could keep my eyes on the road rather than glued to the speedo.
Are any manufacturers reading this?
Steven Ford
Competing interests: three, now lapsed, speeding tickets
Competing interests: No competing interests