Providing free flowing motorways with convenience of access to every local
destination is the ultimate in having conflicting parameters - and why widen?
it is the junction capacity which puts the tail-backs on to the open sections.
As well demonstrated in Glasgow with (still) failing concrete structures
(probably due to poor design and implementation control when the rush to build was
on - when site huts cannot get gas fires because the wholesalers have run out
of stock - as happened when Glasgow's motorway was smashing through the city
- what else is in short supply? eg specialised concrete additives, the
specified re-bar etc and then what does the site foreman do to keep the output up?)
When some of the excessive number of slip roads were closed off the flow
through the core section actually improved noticably, so much so that some of the
closures are practically permanent. The M4 would probably flow much better if
it had fewer accesses on the inner section, and the M4 bus lane is a further
case of less is more - by extracting a particular class of traffic, and
homogenising the use of each sector of the carriageway both experienced improved
journey times (OK so the buses and coaches saw a massive improvement but....)
cue song We're on the road to Nowhere
Dave H
Glasgow
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