In article , tim
[snip]
the second lane. Between Junction 11 (Chertsey) and Junction 12 (M3) only
vehicles wanting to leave on the M3 are usually to be found in the
nearside
lane, because it is a short distance. The advantage is that it gives
vehicles a much better chance of getting into the exit lane well in
advance
of the junction, and stops much of the last-minute darting for the exit
that
you find elsewhere.

But this isn't why it is like that.

It is because when they widened to 4 lanes it was too expensive
to rebuild the junction so the extra lane was only built between
the junctions. As you say it works well, but I don't think that they
often do it that way by design.

The motorways in Washington New Town (was County Durham, now Tyne & Wear) are
all like that. It is obviously planned like that. It works well, as it
should.

Michael Bell
--

"Michael Bell" wrote in message
...
In article , tim

But this isn't why [M25 between A3 and M4] is like that.

It is because when they widened to 4 lanes it was too
expensive to rebuild the junction so the extra lane
was only built between the junctions. As you say it
works well, but I don't think that they
often do it that way by design.

The motorways in Washington New Town (was County Durham,
now Tyne & Wear) are all like that. It is obviously planned like that.
It works well, as it should.

I believe that the North Circular was planned and built like that from Hale
End Rd to Palmers Green, and I know that the scrapped plan for Palmers Green
to Bound Green Road inclusive was also like that (2+2 lanes through
junctions and 3+3 between them).

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

Terry Harper wrote:

"Arthur Figgis" ] wrote in message
...
On Mon, 10 Jan 2005 00:19:51 +0000 (UTC), "Terry Harper"
wrote:

Nigeria made the change, and lorries and buses changed first, then cars a
few days later. They did however keep cars off the road for those few
days....

But they must have a horrendous road safety record there, given the
number of widows and orphans who e-mail me details of millionaire TOP
OFFICIALs who have died in TRAGIC AUTOMOBILE ACCIDENTs.

They did, and probably still do. Playing chicken with heavy trucks on a
single lane road doesn't work, and the result is usually an overturned car
on the hard shoulder. Probably makes running a scam preferable to driving a
car for a living:-)

Surely you mean the verge? If there were a hard shoulder then they'd be
stupid not to redesignate it "road" to avoid the problem. And UIVMM most
of the roads around there are unsealed anyway, so the same would apply
to a soft shoulder.

Neil Williams wrote:

On Tue, 11 Jan 2005 10:47:21 +0000 (UTC), "Terry Harper"
wrote:

Really the answer is to provide an extra lane between junctions, so that
there is never any need to merge off a slip road.

I don't like that when driving a slower vehicle (e.g. a minibus)
because it means you are forever moving back and forth.

Only if you stick to the extra lane.

I think most
lorry drivers would probably agree - unless such lanes were
permanently marked with dotted lines to be for turning vehicles only.

They do a similar thing on the A2 between Falconwood and Dartford. The
leftmost lane was designated "local traffic only" and apart from buses,
all vehicles in it had to leave at the next junction. The rules were
relaxed slightly when they found that traffic wasn't always able to
merge, and the roundabouts near the Danson Underpass could not cope with
the traffic volume, so some people were driving the wrong way down a one
way street in order to avoid the jams. The lane is still "local traffic
only" but it no longer all has to leave at the next exit.

The solution is just to have a slip road such that the
slowest-accelerating vehicle you're likely to get on a motorway (say,
an oldish, heavily-laden lorry) can accelerate safely to the
prevailing speed of the inside lane (let's say 60mph or so) without
going absolutely flat out.

There is no single solution - different locations have different
constraints.

That would probably, I'd say, involve doubling the length of a good
proportion of existing sliproads with an upwards slope to motorway
level (the downward ones obviously assisting with acceleration), and
tripling the length of all sliproads which have a give way just before
the motorway is met (such as older services stations). Planning the
merge would also be easier with a longer period alongside the motorway
itself.

To merge traffic safely on the motorway, drivers (even of slower
vehicles) shouldn't need to be slamming through their gears attempting
to accelerate to the prevailing speed when they should be already
thinking about the actual merge.

Even with a decent length to do it, merging can be a problem.

On Mon, 17 Jan 2005 13:11:33 +1030, (Aidan Stanger)
wrote:

I don't like that when driving a slower vehicle (e.g. a minibus)
because it means you are forever moving back and forth.

Only if you stick to the extra lane.

Which, if it is marked as a normal lane and not a sliproad, you are
supposed to do. The designation you suggest, or just marking it as a
sliproad throughout, would of course solve this.

Even with a decent length to do it, merging can be a problem.

Oh, indeed. It's just much more difficult if you're still thinking
about acceleration by the time you should be braking slightly to match
speed and slot in because the sliproad is *far* too short.

Neil

--
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

"Aidan Stanger" wrote in message
...
Terry Harper wrote:

They did, and probably still do. Playing chicken with heavy trucks on a
single lane road doesn't work, and the result is usually an overturned
car
on the hard shoulder. Probably makes running a scam preferable to
driving a
car for a living:-)

Surely you mean the verge? If there were a hard shoulder then they'd be
stupid not to redesignate it "road" to avoid the problem. And UIVMM most
of the roads around there are unsealed anyway, so the same would apply
to a soft shoulder.

Delete the word "hard":-) There was usually a coating of tarmac on some of
the laterite.
--
Terry Harper, Web Co-ordinator, The Omnibus Society
Web Site: http://www.omnibussoc.org/75th.htm
E-mail:
URL: http://www.terry.harper.btinternet.co.uk/

"Neil Williams" wrote in message
...
On Mon, 17 Jan 2005 13:11:33 +1030, (Aidan Stanger)
wrote:

I don't like that when driving a slower vehicle (e.g. a minibus)
because it means you are forever moving back and forth.

Only if you stick to the extra lane.

Which, if it is marked as a normal lane and not a sliproad, you are
supposed to do. The designation you suggest, or just marking it as a
sliproad throughout, would of course solve this.

Even with a decent length to do it, merging can be a problem.

Oh, indeed. It's just much more difficult if you're still thinking
about acceleration by the time you should be braking slightly to match
speed and slot in because the sliproad is *far* too short.

The usual practice seems to be to mark the slip lane with long-dash markers
for the last half mile or so before and after the junction. Where you have
junctions close together, like on the M25 near Heathrow, the long-dash lane
separator extends virtually between the junctions. Once you are in that
lane, you are effectively committed to exiting.

I recall one road on the outskirts of Pittsburgh, where the signs say "Right
Lane Must Exit", and they mean it. There are traffic signals on the through
lanes, and no way to merge back in. It's about a 10-mile diversion, I
believe.
--
Terry Harper, Web Co-ordinator, The Omnibus Society
Web Site: http://www.omnibussoc.org/75th.htm
E-mail:
URL: http://www.terry.harper.btinternet.co.uk/

In article ,
(John Ray) wrote:

John Rowland wrote:

Anyway, Queen Square is all clockwise except for the southeast
corner, which is two way... now *that's* confusing.

Russell Square now has a Northbound bus lane on the East side, so that
that side is 2-way. However, if I remember correctly, there is a
physical barrier (kerbstones or similar) between the two lanes.

And a weird new cycle contraflow lane on the West side which appears to
continue into the South side which has no such lane. Anyone understand it?

--
Colin Rosenstiel