Ken Wilshire wrote:


Modern downward tinkering of speed limits is practically all about
anti-car, not common sense, cf ever increasing swathes of 20 mph
zones, etc.

Cite?

I was with you until that. Some 20mph zones are excessive (the
ludicrous one on the approach to Ambleside was one example but it's
now mostly been increased to 30, and most people did 30 anyway), but
many or most of the ones on estates are justified.

That said, the better approach on newer residential estates is to
design the road layout with curves and natural chicanes (on-street
parking) so the natural speed is 20mph or below, then it doesn't
matter if the limit is the default 30. This is done to great effect
on many Milton Keynes estates, especially newer ones.

Neil

Chris / Neil

I was specifically thinking about the London Borough of Merton which
for the last three years has been going through the borough converting
whole swathes of streets (not enclosed estates) into 20 mph zones
(from 10 to 20 roads at a time!). The SW19 and SW20 postcode areas.
Minutes of the Street Management Advisory Committee meetings can be
found he http://www.merton.gov.uk/council/com...tee&com_id=221

Okay, so having looked at those minutes, specifically
http://www.merton.gov.uk/democratic_...eports/146.pdf

I see the following with regard to that policy:

2.1 It is the Council¢s policy to improve road safety by reducing
vehicular speeds and volume on borough roads. The key objective of these
proposals are to convert existing traffic calmed roads within the
proposed areas into 20mph zones / 20mph speed limits. The majority of
roads have traffic calming measures in place, therefore minimum
changes are required for the introduction of these measures.

2.2 20mph zones / 20mph speed limits are dedicated areas where improving
safety and maintaining the quality of life for local residents takes
precedence over the general objective to ease traffic flows.

2.3 For a 20mph zone, traffic calming features in the form of road
humps; speed cushions; road closures; one way systems; pedestrian refuge
islands and road narrowing are required to achieve a legal and
self-enforceable zone. A 20mph speed limit, however, does not require
any form of traffic calming features as part of the legal process. Signs
and road markings are mandatory within zones and limits.


So it's not "anti-car, not common sense" - it's "pro-resident". Indeed,
if the above is correct (and surely there's some liability if it isn't)
then although you can see 20 signs sprouting, they are only sprouting in
areas where there's already traffic calming in place. So I can't see
that any high-speed routes are being lost to the 20 zones.

Indeed, referring to para 2.3 - if I had the choice between driving
along a 30 with lumps in the road, and a 20 that was plain, I'd go for
the latter, and I assume most drivers would. I resent speed bumps much
more than I resent low speed limits.

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