JB wrote:

JNugent wrote:

Again, this is an obvious point. Those who claim that you can't build your
way out of congestion should stop for a moment and ask themselves what would
happen in London if the M25 (including the Dartford Crossing) was closed to
traffic.

And people that do think that you can build your way out of congestion
should stop for a moment and ask themselves if the M25 does work at
8am on a rainy Monday morning in December.

Compared to the alternative(s), of course it does, both for the traffic
travelling on it and for the roads it relieves (Dorking, anyone?).

Prior to the M25 hardly anyone would have considered living one side
of London and working the other. Now the M25 exists people do.

People keep saying this, and it is possible that there are a few examples,
but by and large, the same quantification ("hardly anyone") applies both
before and after the construction of the M25. Living in Kingston and working
in Brentwood is not new.

People will put up with a certain level of 'crapness' in a journey. If
it is too crap then they either won't start doing it or will stop
doing it.

And?

The M1 is being expanded into 4 lanes into London, will that solve the
congestion problems on that road? It would if only the vehicles that
currently use it, use it in the future. But as the road will become
less crap when the 4 lanes open, then more people will start using the
M1, until it degenerates again into the current level of crapness. So
you may get a small window of improvement, but it fixes nothing over
time.

If you were right about that (you aren't), every town and village along the
line of the routes superseded by the motorway network (cf: Holmes Chapel, or
Talke Pits, or Stone) would be as congested today as they were in the summer
of 1958. They aren't.

Similarly, if you were right about that (you aren't), it would still take 12
hours to drive from (say) Preston to London. It doesn't, except in unusual
conditions where a road is closed due to an accident or incident trapping
traffic on a motorway with no means of escape until the incident is cleared.
I'll admit that one good thing about the A50 was that you could abandon your
journey, do a three-pointer and go home.