The Findings Of Professor Mervyn Stone
Safe Speed Press information

 
 
 release date: 26th June 2004 number: PR130

 
The Findings Of Professor Mervyn Stone

Email "wrapper":
 

News  for immediate release attached
 

The BBC Radio 4 "Today Programme" appointed a highly respected professor of statistics to examine the case for and against speed cameras:

Mervyn Stone, emeritus professor of statistics at University College London, said:

"The "roll out" of safety cameras by separate Safety Partnerships was initiated by DoT. Its management was placed in the hands of the private sector company PA Consulting Group. This "cost recovery" program has failed except for the HMT requirement that it should be self-financing. There has been a failure to design the program so that it would provide the information needed to evaluate alternative ways of getting the benefits of speed camera enforcement. The emphasis on political acceptability has led the program down a cul de sac in which essential public trust has been lost. The mistakes already made should be openly recognised, and the program should be subjected to a root and branch rethink."

Please see the attached document for much more.

Original attachment: http://www.safespeed.org.uk/pr130.doc (text also reproduced below)
 

Notes for editors:

The Today programme has placed a very different spin on professor Stone's findings. The 11,000 word report from Professor Stone will soon be published to the following web page:

http://www.bbc.co.uk/radio4/today/reports/politics/speedcameras2_20040624.shtml

The Today Programme took evidence in writing and in person from Paul Smith of the Safe Speed road safety campaign, and from Robert Gifford of PACTS. The written evidence is also due to be made available from the above noted web page. Paul Smith's evidence document is already available from:

http://www.safespeed.org.uk/againstcameras.doc

About Safe Speed:

Since setting up Safe Speed in 2001, Paul Smith, 49, an advanced motorist and road safety enthusiast, and a professional engineer of 25 years UK experience, has carried out about 5,000 hours of research into the overall effects of speed camera policy on UK road safety. We believe that this is more work in more detail than anything carried out by any other organisation. Paul's surprising conclusion is that overall speed cameras make our roads more dangerous. Paul has identified and reported a number of major flaws and false assumptions in the claims made for speed cameras, and the whole "speed kills"  system of road safety. 

The inescapable conclusion is that we should urgently return to the excellent road safety policies that gave us in the UK the safest roads in the World in the first place. 

Safe Speed does not campaign against speed limits or appropriate enforcement of motoring laws, but argues vigorously that automated speed enforcement is neither safe nor appropriate. 
 

Contact Safe Speed: 

web: http://www.safespeed.org.uk 
email : psmith@safespeed.org.uk 
telephone: 01862 832000 anytime. 
mobile: 07799 045553 
note: the mobile does not work well at our office. Always try land line first. 
Location: North Scotland 

We are available for press and media interviews.

Original attachment:

PR130:  The Findings Of Professor Mervyn Stone.


News: For Immediate Release:
 

In the recent tribunal held by the Radio 4 “Today Programme” to determine the overall case for speed cameras, Professor Mervyn Stone suggests the following conclusions and caveats:

Conclusions and Caveats:

1) Some international studies show a localised benefit from speed cameras, but:

  • Highly visible speed cameras create “gaming behaviour” where road users slow only in the vicinity of speed cameras.
  • In a Welsh study the total potential benefit from speed camera across the whole area was presently only about 1.5% of accidents.
  • (exact quote): “But no-one can say that these localised savings may not be outweighed by an irritation-induced increase on the 99% plus of the road network that is well away from any safety camera.”
  • It appears that the measurable effects of a camera may extend no more than a few hundred yards.
  • (exact quote): “But everyone can see that the measurable outcome of cameras is a very localised reduction in speeds.”
  • A New Zealand study suggests that hidden speed cameras might be more effective.  


2) (exact quote): 

“The “roll out" of safety cameras by separate Safety Partnerships was initiated by DoT. Its management was placed in the hands of the private sector company PA Consulting Group. This “cost recovery" program has failed except for the HMT requirement that it should be self-financing. There has been a failure to design the program so that it would provide the information needed to evaluate alternative ways of getting the benefits of speed camera enforcement. The emphasis on political acceptability has led the program down a cul de sac in which essential public trust has been lost. The mistakes already made should be openly recognised, and the program should be subjected to a root and branch rethink.”


3) Professor Stone criticises strongly the Official DfT Speed camera public acceptance survey questions calling them a “loaded instrument”.

4) (exact quote) 

“The three-year DfT report was released from a politically-dictated embargo on June 15th. As I implied in my speed camera judgement, its analysis of the data from the 24 police force areas makes no quantitative allowance for rttm. (regression to the mean) Section G3 of the report gives reasons for thinking that the established statistical phenomenon of regression to the mean [rttm] will not apply in full measure". I interpret this to mean that the authors acknowledge that the estimates of savings of casualties and accidents in the Executive Summary should be taken as upper bound estimates. Will the public be made sufficiently aware of this qualification? Was the minister?”


5) (exact quote): 

"Turning now to the written statement of Mr Smith, the reader should know that I have downloaded most of the files, acquired most of the papers to which he referred, and gone through them with as much care and attention as I could summon. In itself, an achievement of sorts, but paling into insignificance compared with that of Mr Smith himself. He has single-handedly taken on the road safety establishment. He has brought to the fore hitherto neglected questions with admirable forensic skill and logic. He is a gad fly par excellence whose bite must have already irritated many in the road safety world who prefer a quieter way of dealing with issues. His piece is a powerful polemic attacking the interpretation that others have placed on the body of evidence about the relationship between speed cameras and accidents."


6) (exact quote): 

“It is, of course, possible that Mr Smith is right and that the frightful accumulation of deaths from the “fatality gap" ought to be laid at the door of irritation with visible speed cameras.” 


7) (exact quote): 

“A second strand of Mr Smith's case rests on his questioning, verging on the censorious, of the propriety of attributing causality to the role of speed in empirically established relationships between speed-based measures (such as its mean and coefficient of variation) and accident numbers. In this, I think he has a valid point. But it is one whose proper place is in the scientific discourse that organisations such as TRL Ltd should now be willing to entertain.” [In this we believe that Professor Stone refers to the section in our document titled the “1mph lie”]

Professor Stone on Paul Smith’s case:

Professor Stone did not accept Paul Smith’s proposed “anti-camera” case in full. However, Two significant misinterpretations may have contributed to this judgement.

1) Professor Stone says: “His (Paul Smith’s) program requires that effort should rather be put into ensuring that the bulk of our driving community has driving skills on a level with those of an Advanced Motorist or a product of the Hendon Police Driving School perhaps high enough to earn a Licence to Speed". This is incorrect. Paul Smith does advocate improvements to road safety based on four related methods, none of which involve such a wide raising of standards.
 

  • Remedial training for those causing accidents or found driving carelessly. The objective here is really to avoid mistakes being repeated. Such individuals would pay for their own remedial training.
  • The Government should introduce incentives to motivate voluntary advanced driver training for those that might be persuaded, but also to send a message to other drivers that they still have plenty more to learn. Advanced driver training would be based around new national standards driving and would be supported by an official advanced driving licence.
  • The Government should measure and develop our national road safety culture. It is this safety culture that is primarily responsible for delivering the safest roads in the world, and it is nowhere near as good as it could be. Yet no efforts have ever been made specifically to measure or improve it.   
  • The Government must ensure that all road safety information is highly accurate and not liable to misinterpretation. For example at present Mr Smith believes that we have a serious problem because the messages given by current public policy (speed cameras) and current advertising is send very flawed messages to road users about the common causes of accidents.
 
2) Professor Stone says (referring to “the fatality gap”): “Mr Smith argues that this must be a causal relationship (at least in part) because he can find arguments against all the other possible explanations he can think of.” But Mr Smith does not make this mistake. The following passage from Mr Smith’s evidence document illustrate the point:
“But simple correlation does not imply causation. In order to work towards establishing that modern speed camera policy may have caused the loss of trend in the fatality rate, we need to consider and perhaps eliminate other potential causes. We have done a lot of work in this area and most of the potential causes can be quickly eliminated with a high degree of confidence. 

Then we need to investigate possible mechanisms whereby speed cameras policy could affect road safety for the worse. There are many. We maintain an 18 point list.

It is presently a matter of judgement rather than fact but I am now very certain that the loss of trend has been caused by speed cameras and the policies that support them. The evidence is sufficiently compelling to demand an immediate cessation of all speed camera operations pending a full scientific investigation. 

This viewpoint is strongly supported by other observations throughout this document and on the Safe Speed web site. In particular it is worthy to note that we achieved the safest roads in the world without a high degree of emphasis on speed limit compliance and with the vast majority of motorists exceeding the speed limit frequently.”


Finally Professor Stone does not address the subject of the fundamental basis of road safety. Mr Smith asserts that our road safety record results from the quality of the average (i.e. arithmetic mean) driver. Any tiny incremental change in average driver quality is likely to produce a result measurable in lives saved or lives lost, depending on whether the change was for the better or the worse.

Paul Smith comments: “Professor Stone’s intelligent involvement in the road safety debate is extremely welcome. For too long UK road safety has been bogged down in dogma – and most of the dogma has been based on bad research or false assumptions. It isn’t just speed cameras. Our entire national approach to road safety requires a root and branch rethink."

<ends>

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Created 1/07/2004. Last update 1/07/2004