RE: Scamera research poor sys BMJ
Friday 11th February 2005
Road safety campaign group Safe Speed has drawn attention to research by the prestigious British Medical Journal (BMJ) which highlights "an important and fundamental omission".
Scamera research poor sys BMJ
Cameras not making roads safer: campaign
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Image courtesy www.speedcam.co.uk |
The BMJ paper contains no new research, according to Safe Speed. Instead it analyses available research for content, quality and conclusions. Safe Speed said it broadly agrees with the paper's main conclusions, which are:
- Speed camera research tends to find a benefit "at speed camera sites".
- The quality of the research is very poor.
Safe Speed said it has long been drawing attention to the very poor quality of available research.
Paul Smith, founder of the Safe Speed road safety campaign said, "The main reason for the poor quality of the research seems to be the influence of vested interests. Much of the research has been commissioned by those with an interest in the outcome and this has led to some very bad science.
"However the report completely ignores the factors that we consider the most important. Speed cameras don't just slow us down, they alter the way we think and the things we pay attention to. Most drivers report a very significant shift in the way that they drive in the speed camera era - they pay far more attention to the risk of cameras and the number on the speedo. There is no justification for this change in priorities -- the squandered driver attention to the road ahead is far more important to road safety any general speed reduction.
"It is clearly insufficient to consider the effect of cameras on crashes at speed camera sites. We must also consider the effect on the wider road network.
"Do not make the mistake of thinking that such effects are insignificant. Yes, in any individual the effect is small, but the net effect on 32 million drivers has already cost 8,000 lives according to our best estimates."
Safe Speed reckons that speed cameras are not making the roads safer. "They alter the way we think when we're driving and not for the better. We must scrap all speed cameras and get back to the excellent road safety policies that gave us the safest roads in the world in the first place. Those policies were based on skills, attitudes and responsibilities, and those are the things that really matter."
Discussion
I have now sent a formal response to the BMJ:
Safe Speed Response
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.
[1] http://ip.bmjjournals.com/cgi/content/full/9/4/293
and http://bmj.bmjjournals.com/cgi/content/full/324/7346/1153/a
and (paid work?) 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] www.timesonline.co.uk/article/0,,2-1215962,00.html
[5] www.safespeed.org.uk/problem2.html
=============================================
Hopefully this will be available on the BMJ on line service shortly, possibly on this page:
http://bmj.bmjjournals.com/cgi/content/full/330/7487/331
Safe Speed Response
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.
[1] http://ip.bmjjournals.com/cgi/content/full/9/4/293
and http://bmj.bmjjournals.com/cgi/content/full/324/7346/1153/a
and (paid work?) 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] www.timesonline.co.uk/article/0,,2-1215962,00.html
[5] www.safespeed.org.uk/problem2.html
=============================================
Hopefully this will be available on the BMJ on line service shortly, possibly on this page:
http://bmj.bmjjournals.com/cgi/content/full/330/7487/331
Paul Dishman said:
Anyone can post a rapid response to a BMJ article, but remember that this is a respected medical publication so keep it literate, well spelt and logical.
>> Edited by Paul Dishman on Saturday 12th February 01:56
So what’s logical about a policy that has failed to reduced road deaths significantly since it's creation, I find your comments odd! do you mean that if an individual has not the literary skills or spelling ability he/she is not qualified to place his/her point view? As a voter and that’s me weather I can spell or strings word together the same as some of the elegant bollox about camera claims it should not matter. If this policy were reducing deaths then fair-enough but when it is not your comment are worthless. You see that’s where I get totally frustrated with people who have the smart comments but never address the issue of why deaths have not fallen. That is the aim is it not, well we know this government is heavy into the fines culturs about 1 thousand since 97, maybe I’m wrong and should be asking have the “fines” targets been reached yet.
>> Edited by Sgt^Roc on Saturday 12th February 19:01
I cannot agree too strongly with speed safe; a more succinct summary might be:
Would you rather be hit by an observant motorist who had been doing 35mph and slowed when you stepped out to 10mph or hit by the automon, still driving legally, but no attention and thus doing 30 when he hits you because he's only just realised the hazard?
Graham Hill once said "any fool can drive fast enough to be dangerous" Lower speed does not inherently mean safe.
Would you rather be hit by an observant motorist who had been doing 35mph and slowed when you stepped out to 10mph or hit by the automon, still driving legally, but no attention and thus doing 30 when he hits you because he's only just realised the hazard?
Graham Hill once said "any fool can drive fast enough to be dangerous" Lower speed does not inherently mean safe.
Sgt^Roc said:
[quote=Paul Dishman]Anyone can post a rapid response to a BMJ article, but remember that this is a respected medical publication so keep it literate, well spelt and logical.
>> Edited by Paul Dishman on Saturday 12th February 01:56[/quote
So what’s logical about a policy that has failed to reduced road deaths significantly since it's creation, I find your comments odd! do you mean that if an individual has not the literary skills or spelling ability he/she is not qualified to place his/her point view? As a voter and that’s me weather I can spell or strings word together the same as some of the elegant bollox about camera claims it should not matter. If this policy were reducing deaths then fair-enough but when it is not your comment are worthless. You see that’s where I get totally frustrated with people who have the smart comments but never address the issue of why deaths have not fallen. That is the aim is it not, well we know this government is heavy into the fines culturs about 1 thousand since 97, maybe I’m wrong and should be asking have the “fines” targets been reached yet.
>> Edited by Sgt^Roc on Saturday 12th February 19:01
I'm not sure that I understand what you are getting at.
If you want the BMJ to publish your Rapid Response you have to make it (your response) logical, literate and well spelt because otherwise they (the BMJ) will edit it out.For example calling the author "a lentilist tosser" won't be published neither will using words like "bollox" regardless of the merits of your argument.
I don't think that the speed camera policy is at all logical which is why I posted a short response opposing it. I expect most PH'ers would be opposed to scamera policy and just wanted to give some advice as how to get our point of view over in this particular publication
safespeed said:
Peter Ward said:
Well done, Paul! Your letter has been published on the BMJ website. It looks complete and unedited.
I can't find it - am I being thick?
Sorry, was away for w/e.
Click on the URL you specified to reach the paper. Then click on "Read responses to this article" at top RHS. This leads to your letter plus other stuff there now. Hope this helps.
Edited to say: Having just read the responses, the comments are in line with our view stated here that you can't say the studies are poor and also support speed cameras. There are various anecdotes re speeding. Of course none of this will make any difference, but there's a huge groundswell of opinion against cameras. Even my parents, both almost 70 now, see them as nothing to do with road safety.
>> Edited by Peter Ward on Sunday 13th February 17:33
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