Safe Speed Forums

http://www.iam.org.uk/Pressroom/Fact_Sh ... c21001.pdf


my response

Dear Sirs,

I am writing to object to the content of :

Safety Cameras Fact Sheet Number 21/001

http://www.iam.org.uk/Pressroom/Fact_Sh ... c21001.pdf

You state:

Chance of driver being involved in an accident For every 1 mph reduction in a driver’s speed, the chances of being involved in a crash decrease by 5%. (source: Transport Research Laboratory)

This is nonsense and has been disproved by both the SafeSpeed Campaign and the Association of British Drivers See:

http://www.abd.org.uk/onemph.htm
http://www.safespeed.org.uk/trl421.html

Even if you reject their view it is worth understanding that the source for the claim was not TRL, as TRL421 (the report where this claim was maid) was actually a report on existing research. No actual trials were conducted by TRL.

In any case for this claim to be true it implies that crashes could be eliminated completely by reducing speeds from 60 or 70mph to 50 or 40mph. Given the number of roads in the UK that continue to experience accidents (sometimes in greater numbers) after having a speed limit cut from 60 to 40 or 70, 50 suggests the claim is flawed.

Surely as an advanced driving organisation we should be seeing beyond the over simplified ‘speed kills’ messages which lead people to think that they are safe drivers as long as they stick to the speed limit. We need to get the real facts across to members and the public.

Lastly the only people who call speed cameras safety cameras are speed camera partnerships. Speed cameras measure a vehicles speed. They do not measure if the driver is safe, fit, or legal. To call them safety cameras helps confuse the public that they are there for road safety. £750M in fines and 12M prosecuted drivers can tell you their real purpose.

I would very much like to feel able to join the IAM and support the organisation, but until they stop associating themselves with the 'speed kills' message and other such nonsense I shall not do so.

They could be doing a lot more good in helping to improve driving attitudes and road safety, but they need to change their stance considerably.

Best wishes all,
Dave.

The 5% per mph is presumably not meant to be linear (otherwise if you reduce the limit further, you would see greater reductions than just 5% per mph).

Let's assume just for a minute that you really do see 5% reduction in accidents per mph slower that the mean speed is on a particular stretch.

For a 20mph reduction, you'd see (1 - 0.95^20)*100 = a 64% reduction in accidents - which I presume is still quite far from the observed stats.

They are definitely coming our way. But big things are hard to get moving.

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety