Scamera Partnerships win on points
Discussion
This morning I realised that we might have been missing the point of the way the Partnerships have been heading recently.
We've been highlighting the fact that, overall, KSIs are up despite the increase in camera numbers.
They've been highlighting the "40% reduction in KSIs at camera sites".
Maybe it's just me, but I think I've been missing the importance of this. It's as if they've not been answering the same question, but in fact I think everything's playing to their agenda.
Why are we now to have cameras on an 70mph section of the M4? Because "KSIs are reduced at camera sites". Therefore, increase the number of camera sites. Dramatically, as a matter of policy, and as a direct result of the two statements above.
Every time someone points out that KSIs are up overall, it actually supports the Partnerships' goal of erecting more and more cameras, because of the "40% reduction in KSIs at camera sites".
Therefore, it seems to me that the our aim should not (just?) be to keep pointing out that KSIs are up overall, but to get behind the "40% reduction..." and prove it's spurious. Only that way can we hope to head off what's now happening.
The trouble is, that's a hard thing to do because it requires an understanding of statistics that the general population does not understand.
Am I right or have I completely missed the point? If so, just how do we do this?
We've been highlighting the fact that, overall, KSIs are up despite the increase in camera numbers.
They've been highlighting the "40% reduction in KSIs at camera sites".
Maybe it's just me, but I think I've been missing the importance of this. It's as if they've not been answering the same question, but in fact I think everything's playing to their agenda.
Why are we now to have cameras on an 70mph section of the M4? Because "KSIs are reduced at camera sites". Therefore, increase the number of camera sites. Dramatically, as a matter of policy, and as a direct result of the two statements above.
Every time someone points out that KSIs are up overall, it actually supports the Partnerships' goal of erecting more and more cameras, because of the "40% reduction in KSIs at camera sites".
Therefore, it seems to me that the our aim should not (just?) be to keep pointing out that KSIs are up overall, but to get behind the "40% reduction..." and prove it's spurious. Only that way can we hope to head off what's now happening.
The trouble is, that's a hard thing to do because it requires an understanding of statistics that the general population does not understand.
Am I right or have I completely missed the point? If so, just how do we do this?
spot on Peter. One of the problems with the figures is as follows.
A stretch of road has an average accident rate of say 10/year for 10 years (with between 0 and 20 each year). In the 11th year there are 20 accidents - no reason for the increase from the average, just random distribution of numbers. Camera installed. 12th year 12 accidents, ie back to close to the average - 40% year-on-year reduction following the installation of the camera, and yet still 20% above the average.
A stretch of road has an average accident rate of say 10/year for 10 years (with between 0 and 20 each year). In the 11th year there are 20 accidents - no reason for the increase from the average, just random distribution of numbers. Camera installed. 12th year 12 accidents, ie back to close to the average - 40% year-on-year reduction following the installation of the camera, and yet still 20% above the average.
"Regression to the mean".
Paul at Safe Speed has been pushing this for years, and the scamera pratnerships have acknowledged that they are aware of the effect, but do not take it into account.
It is spin of the highest order, and used to roll out more and more cameras - instead of taking measures which might actually help road safety, so by default they are killing people.
Paul at Safe Speed has been pushing this for years, and the scamera pratnerships have acknowledged that they are aware of the effect, but do not take it into account.
It is spin of the highest order, and used to roll out more and more cameras - instead of taking measures which might actually help road safety, so by default they are killing people.
Have now noticed that if accidents rise at a cameras site then all of a sudden it's not statistically significant as they are dealing wil such small numbers. 
Surely this is the same if numbers drop.
I'm waiting for this one
3 deaths drop to 2 deaths a fall of 33% (1 in 3)
3 deaths rise to 4 deaths a rise of 25% (1 in 4)
Surely this is the same if numbers drop.
I'm waiting for this one
3 deaths drop to 2 deaths a fall of 33% (1 in 3)
3 deaths rise to 4 deaths a rise of 25% (1 in 4)
They have put scameras in the temporary roadworks on the A47 through Peterborough. Guess what, I saw the first crash I've ever seen on that stretch a few days ago. Scameras can lead to accidents too.
They can not and never will be a safety device, they just take a picture and issue a tax demand.
They can not and never will be a safety device, they just take a picture and issue a tax demand.
Size Nine Elm said:Spot on. Also, some mathematical professor was tasked to see if the government figures were indeed misleading (heard this debated on the radio): he had to concede they were deeply flawed, despite the fact he admitted he was biased for speed cameras. If only the general public were as smart as us.....
"Regression to the mean".
Paul at Safe Speed has been pushing this for years, and the scamera pratnerships have acknowledged that they are aware of the effect, but do not take it into account.
It is spin of the highest order, and used to roll out more and more cameras - instead of taking measures which might actually help road safety, so by default they are killing people.
www.safespeed.org.uk/rttm.html
www.safespeed.org.uk/moreorless.html
(I was actually in favour of the speed camera policy, until I heard this very debate. This is what turned me against the dark side)
BliarOut said:
They have put scameras in the temporary roadworks on the A47 through Peterborough. Guess what, I saw the first crash I've ever seen on that stretch a few days ago. Scameras can lead to accidents too.
They can not and never will be a safety device, they just take a picture and issue a tax demand.
Maybe it's the roadworks and not the camera?
Double Play said:
They have put scameras in the temporary roadworks on the A47 through Peterborough. Guess what, I saw the first crash I've ever seen on that stretch a few days ago. Scameras can lead to accidents too.
They can not and never will be a safety device, they just take a picture and issue a tax demand.
Maybe it's the roadworks and not the camera?
Pretty unlikely... They have had roadworks on this stretch many times before without incident. Funny the accident happened right under the 40 MPH scam
james_j said:
I could quite easily find a site where there have been a couple of accidents recently.
I'm sure that if I planted an oak tree on the verge, the accident rate would reduce.
...but I wouldn't be stupid enough to suggest that the oak tree had anything to do with it...
Precisely -- unless you were paid to suggest it, paid to publicise it, paid to enforce the planting of more oak trees, and reaped the benefits of the acorns produced from them.
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