Why does the UK not have any D2+1 roads?
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Why does the UK not have any D2+1 roads?
Re: Why does the UK not have any D2+1 roads?
They also have the disadvantage that if something breaks down on the 1 side, the road is blocked. As Al says, they can't be much cheaper than just building D2
Re: Why does the UK not have any D2+1 roads?
https://www.google.co.uk/maps/@51.73264 ... 8192?hl=en
There are also 3 lane roads where the solid white alternates, the Louth bypass is one example. This is not some old S3 road from the 50's of 60's it was built in the late 1980's
https://www.google.co.uk/maps/@53.35379 ... 8192?hl=en
I have seen similar layouts elsewhere in Wales and Scotland as well as parts of the USA, they are basically climbing lanes in most cases.
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Re: Why does the UK not have any D2+1 roads?
Its purpose is to provide guaranteed overtaking opportunities to break up platoons of traffic on long distance routes, so is normally provided with overtaking provision in both directions; which differs from the intention of traditional climbing lane layouts.
Re: Why does the UK not have any D2+1 roads?
This is the best compromise as this allows you to get past a broken down vehicle - Keith's A477 example has had to provide a hatched out area for the same purpose which means you've built a D2 by default.Glen wrote: ↑Thu Jan 06, 2022 10:12 We have WS2+1, which is a relatively recent design standard, which has the same purpose, but without a central reservation.
Its purpose is to provide guaranteed overtaking opportunities to break up platoons of traffic on long distance routes, so is normally provided with overtaking provision in both directions; which differs from the intention of traditional climbing lane layouts.
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Re: Why does the UK not have any D2+1 roads?
Re: Why does the UK not have any D2+1 roads?
I bet that was built as D2 though and the lane removed laterKeithW wrote: ↑Thu Jan 06, 2022 08:58 Well there is an example in Wales on the A477 here
https://www.google.co.uk/maps/@51.73264 ... 8192?hl=en
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Re: Why does the UK not have any D2+1 roads?
Re: Why does the UK not have any D2+1 roads?
I don't think so, according to the wiki the Kilgetty and Stepaside bypass was only opened in 1984 with less than half a mile of it being D2. The main reason for not being D2 seems to have been the cost of digging the cutting.Herned wrote: ↑Thu Jan 06, 2022 11:12I bet that was built as D2 though and the lane removed laterKeithW wrote: ↑Thu Jan 06, 2022 08:58 Well there is an example in Wales on the A477 here
https://www.google.co.uk/maps/@51.73264 ... 8192?hl=en
https://www.sabre-roads.org.uk/wiki/ind ... title=A477
From the SABRE Wiki: A477 :
The A477 provides the link from A40 at St Clears to the holiday venues on the Pembroke peninsula and the ferry port of Pembroke Dock (this part being part of the Trans European Road Network linking Europe to Ireland). It then connects the Pembroke peninsula to the area north of the Milford Haven estuary via the Cleddau Bridge which opened in 1975. The route prior to the bridge required either a ferry crossing to Neyland or a 40-mile detour
Re: Why does the UK not have any D2+1 roads?
Adding a couple of Wide S2 sections to the A19 between Thirsk and York certainly helped a lot, to the extent that Talivans are now a frequent sightFenlander wrote: ↑Thu Jan 06, 2022 11:11 The easiest way to upgrade parts of the A17/A16/A47 and no doubt many other roads round here would be with the odd bit of S2+1. It doesn't need to be Motorway, it doesn't even need to be dual carriageway, just give us the odd bit of clear road to get past the slower stuff safely.
https://www.google.co.uk/maps/@54.11872 ... 8192?hl=en
Re: Why does the UK not have any D2+1 roads?
I'm pretty sure it was built with the hatching. Spin the camera around (use the 2011 images so you can see it without the temporary barrier) and you'll see an arched bridge with the start of a left turn lane underneath it. The edge of that lane is very close to the cutting face. If it had been built with two lanes, the cutting would have needed to be wider to accommodate the left turn lane, the bridge span longer, and the scheme more expensive.Herned wrote: ↑Thu Jan 06, 2022 11:12I bet that was built as D2 though and the lane removed laterKeithW wrote: ↑Thu Jan 06, 2022 08:58 Well there is an example in Wales on the A477 here
https://www.google.co.uk/maps/@51.73264 ... 8192?hl=en
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Re: Why does the UK not have any D2+1 roads?
So if there was a section of D2, where is it?KeithW wrote: ↑Thu Jan 06, 2022 12:13 I don't think so, according to the wiki the Kilgetty and Stepaside bypass was only opened in 1984 with less than half a mile of it being D2. The main reason for not being D2 seems to have been the cost of digging the cutting.
https://www.sabre-roads.org.uk/wiki/ind ... title=A477
From the SABRE Wiki: A477 :
The A477 provides the link from A40 at St Clears to the holiday venues on the Pembroke peninsula and the ferry port of Pembroke Dock (this part being part of the Trans European Road Network linking Europe to Ireland). It then connects the Pembroke peninsula to the area north of the Milford Haven estuary via the Cleddau Bridge which opened in 1975. The route prior to the bridge required either a ferry crossing to Neyland or a 40-mile detour
Re: Why does the UK not have any D2+1 roads?
Well considering how difficult it was to upgrade the A465 from high standard S2+1 to D2, I think it some cases quite a lot.
Re: Why does the UK not have any D2+1 roads?
I can imagine that WS2+1 is a bit nicer for cyclists on the 1 side, although presumably continental schemes might be more likely to include separate NMU provision throughout.
Re: Why does the UK not have any D2+1 roads?
I've sometimes wondered this about that even rarer beast, the rural S4
Re: Why does the UK not have any D2+1 roads?
Herned wrote: ↑Thu Jan 06, 2022 12:44So if there was a section of D2, where is it?KeithW wrote: ↑Thu Jan 06, 2022 12:13 I don't think so, according to the wiki the Kilgetty and Stepaside bypass was only opened in 1984 with less than half a mile of it being D2. The main reason for not being D2 seems to have been the cost of digging the cutting.
https://www.sabre-roads.org.uk/wiki/ind ... title=A477
Good question - take it up with whoever wrote the wiki entry. My guess was that it was here where one carriageway has been marked down to 1 lane.
https://www.google.co.uk/maps/@51.73037 ... 8192?hl=en
From the SABRE Wiki: A477 :
The A477 provides the link from A40 at St Clears to the holiday venues on the Pembroke peninsula and the ferry port of Pembroke Dock (this part being part of the Trans European Road Network linking Europe to Ireland). It then connects the Pembroke peninsula to the area north of the Milford Haven estuary via the Cleddau Bridge which opened in 1975. The route prior to the bridge required either a ferry crossing to Neyland or a 40-mile detour
Re: Why does the UK not have any D2+1 roads?
I suppose rural S4s probably end up in a 'survival of the unfittest' situation - the ones wide enough to provide a reasonable level of safety will be relatively easy to upgrade to D2, and the ones that aren't will stick around and look unsafe (and probably get changed to something else as well.) I don't know of any NSL rural S4s but I'd imagine they're on roads so quiet that safety's not a huge consideration. I'm not sure any cost savings for "WS4" vs. D2 "from scratch" would ever be worth it.
There's also the fact that it's two overtaking vehicles likely to be meeting at the centre line which are likely to both be going faster, especially if it's quite a short section, I suppose.
Re: Why does the UK not have any D2+1 roads?
or
As your replies seem very contradictory.
I would guess that entire section including the junction was built as D2 and then later, probably after some nasty accidents, it was rebuilt the way it is today
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