Rooney wrote:
> This has nothing to do with which is safer. The only stats posted
> suggest that on average, you are ten times more likely to be killed
> per cycle mile than per car mile. You have to be a bit circumspect
> about drawing conclusions for a particular journey
But that didn't stop you doing precisely that.
> but the fact that
> the stats are based on 'different miles' is a complete red herring.
except that it isn't.
> It is clear - but not by your reasoning/experience. Whether one is
> safer than the other has to take account of the 'per mile' statistic,
> and the fact that they are different sorts of miles is, again,
> irrelevant.
But if you compare miles to Paris for a long haul drive and the miles to
Paris for a short haul flight then they are /not/ different miles: they
are miles to Paris, irrespective of whether on the ground or in the air.
There's not very much of a sample of people cycling over that
distance in a single journey, so you can't really compare bikes.
Comparing the figures you compared is apples to oranges, because you're
comparing longer journeys in the overall figures. That is exactly why
you can't compare same journeys and assume they work the same way.
> What stats would you use to compare the relative safety of driving v.
> the train?
You should compare journeys of basically same start and finish. So if I
want to compare long distances I'd compare something like Inter City
trains to comparable road journeys, or commuting you'd compare something
like Dartford to London on road and track.
Road and rail are easy to compare, because a typical train journey in
the UK will be of the same order of size as a large number of typical
car journeys.
> Or do you also think the stats are of the apple/orange
> variety in this case too?
Not if you compare like with like, which is easy to do with large sample
bases.
> You don't seem to realise that it makes not
> a ha'porth of difference whether the miles are different - what we
> want to know is which form of transport is safer, and the only way to
> measure that sensibly is per unit distance.
You still don't get it, and I'm not the only person here pointing that
out. Why is it better to use per unit distance for all comparisons
rather than per unit journey or per unit time spent travelling, for
instance? The best measure depends what you're measuring, and the fact
is that cars and bikes are used for different typical journeys or
different typical distances, so it's a nonsense trying to directly
compare them.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net
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