Dorset Speed facebook group was shut down!!
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Fleetsbridge Roundabout Traffic lights -
update
Oh dear.
I've just received an FOI response which details how
the council has calculated the £300,000 saving per annum.
It has used an "average cost" per accident
(£68,320) that includes the cost of a death, which vastly exceeds the costs of a
serious or slight injury.
But in the entire history of this roundabout there
have been no deaths! And in any case, as excellently put by Idris in another
recent message,
"The same applies to the largely bogus Dft
valuations for casualties prevented. Taking the £1.6m figure for a fatality as
an example - £550,000 of that is for output supposedly lost
because the worker cannot work - but that is utter tripe because as any 3rd form
economist student knows, output is determined by demand, not availability of
labour and if Joe is not there to make what he used to make, Fred steps in to do
it instead. Completely bonkers - and the same applies to non fatal casualties.
£1m of the rest is a purely notional and hypothetical figure for pain and
suffering avoided and (however much we all want to avoid it) it does not exist
in cash terms in any known ledger this side of the Pearly gates."
The cost of a slight injury is shown as £21,370 a
serious injury £205,060, and a death now a whopping £1,790,200.
Poole Council also seems to like "rounding up" the
numbers it likes to be big, but not the ones it likes to be small !!!
The pre - lights figure (obtained under FOI) is actually 6.6, not 7. So the
accident reduction claimed is actually 6.6-2.7 = 3.9 acc / year, not 4.32.
And then, based on the incorrect 4.32 number, the resulting cost of £295,142 was rounded up to £300,000
for the press article !!!
This number should actually be 3.9* £68,320 = £266,448 - just
shows how a bit of compounded "rounding" can help!
I hope the council are less careless with "rounding" in their other
calculations.
So, here once again is some proper logic:
Using these numbers:
The data (for the roundabout) shows 175 slights and
11 serious, i.e. 6% are serious, no deaths.
Let's be really generous. Although the council is
using just 2 periods of it's data to justify the reduction, but including cost
of deaths of which there were none, it would be scientifically correct to allow
for a contribution to a death as there was a probability that it could
have happened. Even though it would be difficult to imagine a scenario that
would result in one other than total stupidity - certainly that could be blamed
entirely on lack of traffic lights - it's a 30 limit (where it's actually
not safe to speed so it occurs very infrequently) and there are safe pedestrian
/ cyclist barriers / pavements / underpasses.
Let's say the probability of a death is 10% of the
serious count, i.e. 0.6%. It couldn't be much higher because we should have
seen 1 or 2 by now.
So if 3.9 accidents per year are saved, approx 0.23
of these are serious and 0.023 are deaths
So the actual saving would be:
3.68* £21,370 +
0.23* £205,060 +
0.023* £1,790,200
= £78,641 + £47163 + £41174 = £166,978
This is the worst I can get it even factoring in the
ridiculous, unlikely, and absent cost of death, without which it would be well
less than half of what Poole claim to be saving.
And that assumes the 3.9 accident count reduction is
due only to the lights, I am looking forward to seeing the council's logic
behind this which I have asked for by FOI again.
It also assumes that the cost of increasing
congestion, pollution and travel costs and time for thousands of individuals and
businesses every day is £0.
Quite apart from all of this, I certainly look
forward to seeing why it has chosen to completely ignore the fact that in the
first 26 months of full time traffic lights, accidents / year increased from 6.6
to 8.8 and casualties increased from 7.6 to 11.1., but only used periods with 7
years between them when all sorts of other things have shifted.
As far as I can see, the only logic Poole Council
uses is "ignore it when it goes up, use it when it goes down, and round the
numbers up that will help to give the result we want".
Sent: Thursday, December 01, 2011 8:20 AM
Subject: Re: Fleetsbridge Roundabout Traffic lights - a proper analysis -
traffic lights probably INCREASED accidents -POOLE COUNCIL PLEASE RESPOND
Mr Baker, Mr Tite, Poole Council,
I genuinely hope that I'm wrong about this. The
implications go far beyond just one roundabout, if Poole have got this wrong,
what about all of the other things it has done, speed limit reductions, speed
humps, other engineering "improvements". What about it's funding of Dorset Road
Safe? Is the logic Poole has used to do these things equally as flawed? What
about all the money wasted, the deaths not reduced?
If Poole Council believes it is right, why has there
not been a swift and credible response?
Please now respond to this. If there is no adequate
response I will of course be raising complaints about this.
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