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Originally Posted by lynw
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Originally Posted by DanDare
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Originally Posted by wheelnut
There is a report on TV that speed cameras have saved 70 lives 
How the hell do they know that?
And 70 lives over a year is hardly worth counting, unless you are one of the 70 of course :P |
Yeah right, how the hell did they know those 70 people were dead in the first place. But technically speaking they were'nt saved as they couldn't of been in danger in the first place .......or they'd be dead.
Confused......You will be! |
I think they look at the accident rate per year before and after the cameras went in. so the drop reflects the number lives saved. |
Correct, and this is the biggest "mistake" - they usually analyze two years (or not even that) - before and after the camera came in.
Consider the following:
Year Crashes
95 1
96 2
97 1
98 2
99 2
00 1
01 6
02 1
03 1
04 2
From the statistics - a camera would be installed in 2001 (a spike year against the overall trend). The crashes reduced to 1 in 2002. Associated crap from partnership:
"This camera saved 5 lives in one year alone as accidents reduced by 83%"
They all do it.
It would be akin to comparing the death toll in two wars and saying "the use of this tank caused casualties to reduce by 40%" - in other words, there are so many other variables which affect it that they have no hope in hell of judging such a success over a short period of time.
The worrying thing is, with a lot of cameras, the "after" figures are a lot higher than the "before" figures - over many years post-installation.