In article , Michael Bell
writes
I remember calculating at the time that the Swedish change-over cost 2 week's
GNP. That's an awful lot of money. And for what? Junction 8 on the M1 was
designed "wrong way round" in Mrs Castle's time to test the idea of designing
junctions so that they could be changed over to right-hand drive, but the
experiment was never repeated.

Ah, is that the reason? I've always felt that the northbound entry to
the M1 at J8 is by far the most dangerous that I've seen on UK motorways
- first you have to negotiate a rather sharp bend and then accelerate up
to the prevailing traffic speed, usually around 70 mph and merge, all in
about 100 metres, far shorter than anywhere else. I'm surprised that
there aren't more accidents there, and am amazed that the authorities
have never lengthened the slip road.

--
Clive Page

On Mon, 10 Jan 2005 23:19:21 +0000, Clive Page
wrote:

Ah, is that the reason? I've always felt that the northbound entry to
the M1 at J8 is by far the most dangerous that I've seen on UK motorways
- first you have to negotiate a rather sharp bend and then accelerate up
to the prevailing traffic speed, usually around 70 mph and merge, all in
about 100 metres, far shorter than anywhere else. I'm surprised that
there aren't more accidents there, and am amazed that the authorities
have never lengthened the slip road.

They need to lengthen the slip roads on service stations as well. The
worst are the oldest ones, which often have a give way right before
the slip road so you can't start accelerating until you're on it, and
most are far too short and often have tarmac in very poor condition.
Most need, IMO, to be twice as long as they currently are.

Downright dangerous, and the worst thing is that all you'd need to fix
it is a can of paint (and a slightly narrowed hard shoulder) in most
cases. I'm not familiar with J8 as I rarely go south of 13 by car,
but I suspect it's similar.

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.

"Neil Williams" wrote in message
...

They need to lengthen the slip roads on service stations as well. The
worst are the oldest ones, which often have a give way right before
the slip road so you can't start accelerating until you're on it, and
most are far too short and often have tarmac in very poor condition.
Most need, IMO, to be twice as long as they currently are.

Downright dangerous, and the worst thing is that all you'd need to fix
it is a can of paint (and a slightly narrowed hard shoulder) in most
cases. I'm not familiar with J8 as I rarely go south of 13 by car,
but I suspect it's similar.

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

The solution in some places has been to abolish the inside lane between on
and off ramps. Again a paint job, but needing some changed overhead signs.
--
Terry Harper, Web Co-ordinator, The Omnibus Society
75th Anniversary 2004, see http://www.omnibussoc.org/75th.htm
E-mail:
URL: http://www.terry.harper.btinternet.co.uk/

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

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.

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.

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.

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

It seems to work well from Junction 10 (A3) onwards clockwise on the M25. In
general 4 lanes between junctions, three lanes through them.
--
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/

"Terry Harper" wrote in message
...
"Neil Williams" wrote in message
...
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. I think most
lorry drivers would probably agree - unless such lanes were
permanently marked with dotted lines to be for turning vehicles only.

It seems to work well from Junction 10 (A3) onwards clockwise on the M25.
In
general 4 lanes between junctions, three lanes through them.

And do "tortoise" vehicles have to keep changing lanes as they approach and
leave each junction?

If you mark the lanes for turning vehicles only, then you are turning a
four-lane motorway into a three-lane motorway everywhere except close to the
junction.

Much more of a problem is two-lane motorways and dual-carriageways where
lorries and other slow-moving vehicles are allowed to use both lanes. I live
close to the A34 in Oxfordshire and I know only too well that antisocial
lorry drivers regularly clog-up the road because they think it's acceptable
to overtake each other when the overtaking lorry is going only a couple of
mph faster than the lorry it is passing. It seems like common sense that you
don't overtake unless you can complete the manoeuvre quickly, without taking
ages over it. The record that I've observed was a lorry that stayed
absolutely dead-level with another lorry for over three minutes until the
lorry that was being overtaken took the pragmatic approach and braked to
allow the overtaking lorry to pull in ahead of it and open up the road again
to drivers wanting to do more than 40 mph.

"Martin Underwood" wrote in message
...
"Terry Harper" wrote in message
...

It seems to work well from Junction 10 (A3) onwards clockwise on the
M25.
In
general 4 lanes between junctions, three lanes through them.

And do "tortoise" vehicles have to keep changing lanes as they approach
and
leave each junction?

Have you never driven round the M25? Nobody "has" to do anything. The
overhead signs in advance of each junction clearly indicate that the
nearside lane is exit only from that point onwards. Depending on how far it
is between junctions, then vehicles may move to the nearside lane or stay in
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.
--
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:

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.

"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/