A9 dualling

[haggishunter]

There are a couple of signs Northbound and Southbound on the A9 by the Inshes Junction in Inverness saying:

TRANSPORT SCOTLAND

A9 DUALLING

and some much smaller text below... not sure what that says as was in the outside lane each time and vehicles on my left blocked the sign from view when closer. Does that mean a start at Alvie is imminent?

[m80]

There are a couple of signs Northbound and Southbound on the A9 by the Inshes Junction in Inverness saying:

TRANSPORT SCOTLAND

A9 DUALLING

and some much smaller text below... not sure what that says as was in the outside lane each time and vehicles on my left blocked the sign from view when closer. Does that mean a start at Alvie is imminent?

Kincraig-Dalraddy is starting soon, that's all as far as I'm aware.

[Glen]

The contractor is now on site putting in a site compound at Kincraig.

[85CF380]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75. It would transform east-west links in the north, A66 W Cumbria- Penrith, A66 gaps Pen- SC, A64 Malton -Scarboro, Colne - A629 (Keighley) etc? It's all GSJ, alternating overtaking lanes every 2km so at worse you've 2km to wait to pass someone + Emergency Refuge Areas. It would be interesting to know the accident stats for this road. (& yes I realise the DMRB wouldn't allow this design). www.youtube.com/watch?v=tKIGHBV-CpI

The newest design section with a 1metre centre divide starts at 2.33 mins.
This particular German design is 'continuously alternating. it goes from 2+1,to 1+2 & straight back to 2+1 etc etc there are no S2 sections (other than the small transitions).

[djw1981]

The Clackmannanshire bridge is like that 2+1 each way, with overtalking on the second 'half' of the bridge each way

[Nwallace]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75. It would transform east-west links in the north, A66 W Cumbria- Penrith, A66 gaps Pen- SC, A64 Malton -Scarboro, Colne - A629 (Keighley) etc? It's all GSJ, alternating overtaking lanes every 2km so at worse you've 2km to wait to pass someone + Emergency Refuge Areas. It would be interesting to know the accident stats for this road. (& yes I realise the DMRB wouldn't allow this design). http://www.youtube.com/watch?v=tKIGHBV-CpI

Since the main case for the first 2 dualinging mentioned is political; no.

The new Kincardine bridge is an alternating 2+1, only driven it when it's quiet; but then I get the idea it's mostly quiet since it's sharing the load with the Old S2 bridge taking traffic on the Dunfermline route.

[NICK 647063]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75. It would transform east-west links in the north, A66 W Cumbria- Penrith, A66 gaps Pen- SC, A64 Malton -Scarboro, Colne - A629 (Keighley) etc? It's all GSJ, alternating overtaking lanes every 2km so at worse you've 2km to wait to pass someone + Emergency Refuge Areas. It would be interesting to know the accident stats for this road. (& yes I realise the DMRB wouldn't allow this design). www.youtube.com/watch?v=tKIGHBV-CpI

Yes I would agree ideal for the A64 Malton to Scarborough section where overtaking is an issue and accidents caused by driver frustration!

I notice you wisely didn't include the A64 York to Malton due to the much higher traffic volumes and daily congestion dualling that section is the only answer, which I believe is going to be included in the hopgrove roundabout GSJ

[ninja-lewis]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75. It would transform east-west links in the north, A66 W Cumbria- Penrith, A66 gaps Pen- SC, A64 Malton -Scarboro, Colne - A629 (Keighley) etc? It's all GSJ, alternating overtaking lanes every 2km so at worse you've 2km to wait to pass someone + Emergency Refuge Areas. It would be interesting to know the accident stats for this road. (& yes I realise the DMRB wouldn't allow this design). http://www.youtube.com/watch?v=tKIGHBV-CpI

There's a couple of shortish sections of 2+1 near Aviemore. As cars are still limited to 60mph, there generally isn't much time/space for more than 2-3 cars to get past a lorry doing 50mph. The dualled sections are much more effective in clearing a queue of 10-20 cars.

Correct me if I'm wrong but I think the German speed limit for lorries on that sort of road would be 50kmh so there is a larger speed differential when overtaking lorries in particular.

[Glen]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75.

WS2+1 is already used on the A9, A96, A75 and some other trunk roads in Scotland.
It specifically used to provide regular overtaking opportunities in each direction, as opposed to the use of traditional "climbing lanes" on inclines.

And yes, there is a design standard for it.



http://www.sabre-roads.org.uk/wiki/inde ... le=WS2%2B1

[Peter Freeman]

WS2+1 is already used on the A9, A96, A75 and some other trunk roads in Scotland.
It specifically used to provide regular overtaking opportunities in each direction, as opposed to the use of traditional "climbing lanes" on inclines.

http://www.sabre-roads.org.uk/wiki/inde ... le=WS2%2B1

Why do you refer to this as 'WS2+1'? I call that simply S2+1. Is it because the Scottish implementations use it mainly with alternating direction priorities AND usually intersperse it with WS2? Or perhaps it's because of the 1m hard strips on each side?

Alternating direction priority S2+1 is quite common in Victoria (Australia) too. We don't have WS2's (for rural roads) - instead our major rural roads tend to be S2, but with a full hard shoulder on each side.

I must say that I don't like the UK's WS2 standard - it reminds me far too much of the old S3 suicide lanes.

[Bryn666]

The DMRB calls it WS2+1 to differentiate it from a conventional S2+1.

WS2+1 must have 1m hard strips and a (I think) painted 1.5m central divider. Normal S2+1 doesn't.

[Mark Hewitt]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75.

WS2+1 is already used on the A9, A96, A75 and some other trunk roads in Scotland.
It specifically used to provide regular overtaking opportunities in each direction, as opposed to the use of traditional "climbing lanes" on inclines.

And yes, there is a design standard for it.



http://www.sabre-roads.org.uk/wiki/inde ... le=WS2%2B1

I had thought that sort of thing was somewhat discouraged these days. As short sections of dual encourage racing to the end, trying to get past as much as possible before the S2 section hits again. Then there's invariably the Audi who pushes it further than the rest using the hatching to get past the last few before ducking back in. Hence the poor accident record of short stretches.

[Bryn666]

WS2+1 was created so there are run off areas for the occasional Richard Cranium using them.

With warning of a lane drop at 600, 400, and 200 yds it isn't as if you aren't aware of what's going on.

I like WS2+1. We need more of them.

[djw1981]

Is only me then that thinks this would be a great solution for parts of the A9, the A96, A75.

WS2+1 is already used on the A9, A96, A75 and some other trunk roads in Scotland.
It specifically used to provide regular overtaking opportunities in each direction, as opposed to the use of traditional "climbing lanes" on inclines.

And yes, there is a design standard for it.



http://www.sabre-roads.org.uk/wiki/inde ... le=WS2%2B1

I had thought that sort of thing was somewhat discouraged these days. As short sections of dual encourage racing to the end, trying to get past as much as possible before the S2 section hits again. Then there's invariably the Audi who pushes it further than the rest using the hatching to get past the last few before ducking back in. Hence the poor accident record of short stretches.

That section is 1.5 miles of @+!, then 1.5 miles of 1+2 with roundabout at either end.

[Stevie D]

I had thought that sort of thing was somewhat discouraged these days. As short sections of dual encourage racing to the end, trying to get past as much as possible before the S2 section hits again. Then there's invariably the Audi who pushes it further than the rest using the hatching to get past the last few before ducking back in. Hence the poor accident record of short stretches.

WS2+1 is very definitely part of the design standard. But the expectation is that it is for a decent distance (I can't remember but I think it is about 1½ miles in each direction) precisely to avoid the rush that you describe. The taper and hatching at a closing crossover (where the overtaking lanes end) are a lot longer than at a divering crossover (where the overtaking lanes start) to improve the safety at these points. And if the overtaking lanes can end at a roundabout or some other way to avoid a simple lane merge then so much the better.

[MattJackson]

Sorry to change the topic but construction begins today on the first section of A9 Dualling (Kincraig to Dalraddy).

http://www.bbc.co.uk/news/uk-scotland-h ... s-34197501

[orudge]

It seems odd to think that in roughly the same amount of time it takes to dual 7.5km of the A9 (give or take 6 months maybe), 46km of new road plus 12km of dualling will be completed on the AWPR/BT. I guess it's much easier to do offline work than online work, though.

Good news to see the work starting though - we're heading to Aviemore in October so might be able to see the work progressing.

[A9Craig]

I too was surprised by the 24 month construction period. Perhaps that's what you can expect for £7M/mile, or maybe they've been told to stretch it out until Luncarty - Birnam starts in 2017 so the dualling program is seen as seamless.

Edit to add: The northbound overtaking lane just to the south of this scheme will be permanently closed once Kincraig - Dalraddy is completed. DMRB says it's too close to D2. Absolute rubbish in my opinion.

[orudge]

Why can't the WS2+1 just run into the D2? It happens on the A75 for instance. I could maybe understand not wanting a D2 to run into a WS2+1 (with the '2' continuing from the dual carriageway) in case of confusion surrounding speed limits, but don't see why the '2' can't continue from single to dual.

[Bryn666]

That is a **** poor argument, simply saying the DMRB doesn't allow it is ridiculous as a Departure could be obtained.

In any case, 2 lanes going into 2 lanes... what's the problem?