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rhyds wrote: ↑Tue Mar 16, 2021 11:05
The problem is that while the new scheme is a lot better than the old road, its still rather annoying that the standards it is built to require 50MPH SPECS to be applied to a brand new D2.
Its the same kind of engineering reasoning that gives you the 60 limit on the new A556 section. Yes its better than going through Mere and Bucklow Hill, but its a very strange sensation to find yourself on a brand new stretch of GSJ D2 with a posted 60 limit.
Of course you understand the standards are based on simple physical principles such as sight lines and applied factors of safety for certain speeds, plus the risk assessment of plunging 100ft into the Clydach at 70mph? To me looking at the design a lower limit was a no brainer, though I can't quite understand why we're still staunchly opposed to 60mph limits as a country.
At the end of the day this is some of the most challenging terrain a D2 has ever been built through in the UK from a civils perspective. There are compromises on the desired curvatures and roadside obstacles (a giant retaining wall between the two carriageways and another on the north side of the gorge). I'd certainly feel a rush driving down there at 70 and I think that is generally a bad thing.
rhyds wrote: ↑Tue Mar 16, 2021 11:05
The problem is that while the new scheme is a lot better than the old road, its still rather annoying that the standards it is built to require 50MPH SPECS to be applied to a brand new D2.
Its the same kind of engineering reasoning that gives you the 60 limit on the new A556 section. Yes its better than going through Mere and Bucklow Hill, but its a very strange sensation to find yourself on a brand new stretch of GSJ D2 with a posted 60 limit.
Worth remembering the A556 limit is a political condition to offset air pollution concerns and is designed to DMRB's 120km/h spec; whereas the A465 is definitely due to engineering constraints.
I don't think there's much compliance with the A556 60 as it's seemingly never enforced, I certainly get left for dust whenever I use the road; but I don't want to be the driver who gets 3 points for speeding on a road he did all the signage for and a van's lurking on one of the overbridges.
Bryn Terminally cynical, unimpressed, and nearly Middle Age already. She said life was like a motorway; dull, grey, and long.
rhyds wrote: ↑Tue Mar 16, 2021 11:05
The problem is that while the new scheme is a lot better than the old road, its still rather annoying that the standards it is built to require 50MPH SPECS to be applied to a brand new D2.
Its the same kind of engineering reasoning that gives you the 60 limit on the new A556 section. Yes its better than going through Mere and Bucklow Hill, but its a very strange sensation to find yourself on a brand new stretch of GSJ D2 with a posted 60 limit.
Worth remembering the A556 limit is a political condition to offset air pollution concerns and is designed to DMRB's 120km/h spec; whereas the A465 is definitely due to engineering constraints.
I don't think there's much compliance with the A556 60 as it's seemingly never enforced, I certainly get left for dust whenever I use the road; but I don't want to be the driver who gets 3 points for speeding on a road he did all the signage for and a van's lurking on one of the overbridges.
[my bold]
And this is the issue. Should speed limits be set with regards to political rather than safety concerns? That's a very slippery slope, and will (as you've described yourself) lead to widespread noncompliance.
rhyds wrote: ↑Tue Mar 16, 2021 11:05
The problem is that while the new scheme is a lot better than the old road, its still rather annoying that the standards it is built to require 50MPH SPECS to be applied to a brand new D2.
Its the same kind of engineering reasoning that gives you the 60 limit on the new A556 section. Yes its better than going through Mere and Bucklow Hill, but its a very strange sensation to find yourself on a brand new stretch of GSJ D2 with a posted 60 limit.
Worth remembering the A556 limit is a political condition to offset air pollution concerns and is designed to DMRB's 120km/h spec; whereas the A465 is definitely due to engineering constraints.
I don't think there's much compliance with the A556 60 as it's seemingly never enforced, I certainly get left for dust whenever I use the road; but I don't want to be the driver who gets 3 points for speeding on a road he did all the signage for and a van's lurking on one of the overbridges.
[my bold]
And this is the issue. Should speed limits be set with regards to political rather than safety concerns? That's a very slippery slope, and will (as you've described yourself) lead to widespread noncompliance.
It's a tightrope - improved air quality is a reasonable goal; but it's achieved through technological advancements, smarter travel choices, with speed limits being a last resort to my mind.
People don't understand prevailing winds though, take for instance the complete lack of understanding by the general public when we get a load of sand dumped on us from the Sahara Desert. The same would have applied to nuclear fallout no doubt, which is why the whole concept of 'retreat to the Welsh mountains' was a bit of a daft survival idea.
Having smog blow over from the A556 towards Manchester is undesirable, but I dare say the emissions from the new road are far less than the emissions from the old road, which was a crawling line of misery for most of the day.
Bryn Terminally cynical, unimpressed, and nearly Middle Age already. She said life was like a motorway; dull, grey, and long.
Bryn666 wrote: ↑Tue Mar 16, 2021 12:25
Worth remembering the A556 limit is a political condition to offset air pollution concerns and is designed to DMRB's 120km/h spec; whereas the A465 is definitely due to engineering constraints.
I don't think there's much compliance with the A556 60 as it's seemingly never enforced, I certainly get left for dust whenever I use the road; but I don't want to be the driver who gets 3 points for speeding on a road he did all the signage for and a van's lurking on one of the overbridges.
I'd be curious to know what the design speed is for that section of the A465 - would you be looking at 100km/h or less? If so, a 60 limit would be pushing it, especially if you have any departures from standard with sightlines etc. Also bear in mind that weather conditions can be significantly worse compared to the flatlands of Cheshire, so would you really want people tanking along at speed in winter, and suddenly encountering stopped traffic in fog/snow/ice?
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Bryn666 wrote: ↑Tue Mar 16, 2021 12:25
Worth remembering the A556 limit is a political condition to offset air pollution concerns and is designed to DMRB's 120km/h spec; whereas the A465 is definitely due to engineering constraints.
I don't think there's much compliance with the A556 60 as it's seemingly never enforced, I certainly get left for dust whenever I use the road; but I don't want to be the driver who gets 3 points for speeding on a road he did all the signage for and a van's lurking on one of the overbridges.
I'd be curious to know what the design speed is for that section of the A465 - would you be looking at 100km/h or less? If so, a 60 limit would be pushing it, especially if you have any departures from standard with sightlines etc. Also bear in mind that weather conditions can be significantly worse compared to the flatlands of Cheshire, so would you really want people tanking along at speed in winter, and suddenly encountering stopped traffic in fog/snow/ice?
Well, now that you mention it, I find it odd that the A465 in the main lacks any driver information systems or smart features, being similar in conditions at times to the Pennine roads.
jeremai wrote: ↑Fri Feb 26, 2021 08:34
Thanks Andy; great videos as usual. It's so strange seeing the route bypass the Brynmawr roundabout now. I need to get up there to take some new photos once this lockdown is eased.
Should be complete by September according to Twitter:
Thanks. It is difficult accessing the Eastern side of Brynmawr when travelling from Abergavenny...or rather time consuming, driving to Beaufort and doubling back. I just cannot reason why they do not open up the dualling until the Clydach/Lanelly Hill junction...unless it is just to do with the site office access.
A very recent video here, and at the end coming back down earlier this week, just past the new bridge only....though on that section the vibration control was switched off so its a little jumpy.
Chris, yes they are going to spec the whole section at 50mph...currently it is spec'd for the last couple of miles ending over the gilwern gsj. No end date in sight atm which is troublesome as they are not starting the next section, Dowlais top to Hirwaun, it seems until this one is completed.
Thanks for that - looks really good. I visit a friend in Carmarthen about once or twice a year, and I usually do at least one leg of the trip via the Heads of the Valleys to check out the progress. Really looking forward to seeing it for real as the lockdown eases. The dualling project really is pretty spectacular.
Thanks. Yes it really is worth looking at. If you want a distant view you could go up Lanelly hill....probably one of the steepest villages in the country! video here going down. https://youtu.be/znNsxXV2hYI .
I had checked the OS 1:25k on streetmap.co.uk, which I'd always assumed had the most recent available, but it still shows it as a flat roundabout, as do both 1:25k and 1:50k on Bing.
wrinkly wrote: ↑Sat Mar 20, 2021 21:50
I had checked the OS 1:25k on streetmap.co.uk, which I'd always assumed had the most recent available, but it still shows it as a flat roundabout, as do both 1:25k and 1:50k on Bing.
I pay £20 odd a year for osmaps premium, and the 1:25,000 correctly has the mainline above the roundabout. The 1:50,000 is wrong however. Google/maps map and satellite views are up to date.
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Chris Bertram wrote: ↑Sun Mar 21, 2021 09:33
Copyright trap?
I'm no expert on these things (I defer to the likes of Steven) but I doubt it. If every OS error portraying new road schemes is a copyright trap there's an awful lot of them. https://en.wikipedia.org/wiki/Fictitious_entry#Maps
OS 1" and 1:50k maps have been inaccurate in representing recently opened roads for at least 50 years. Roads under construction, too, as recently pointed out in this forum for the Caernarfon bypass.
The BBC has caught onto the 50mph limit on this stretch - (many) days late and a dollar short. The usual gripes about frustrating motorists who have 'endured years of hardship' and disgust that a dual carriageway could have a less than 120km/h design speed. It is quite correctly pointed out that the original road was not NSL either, so there has never been a road higher than 50 through the gorge. I am disappointed, though, that as usual the journalist did not go to the trouble of obtaining a decent ELI5 explanation as to why the design speed is limited, instead choosing to treat readers as dumb-dumbs and saying 'blah safety'.
At the end of the day, with much safer overtaking opportunities, better sight lines and grade separation as well as continuity eventually from Neath to Abergavenny, it's hard to argue that the scheme wasn't worth it. The article talks about the cost implications of a 120km/h line for the road but I am willing to bet that it was simply impossible to achieve.
Truvelo wrote: ↑Mon Jun 28, 2021 00:49
Are you sure it wasn't originally NSL? I don't recall the 50 limit being there twenty years ago.
I'm actually not certain. It was just an assertion made on the old road in the article. It would make sense for the S2+1 to have originally been NSL on the basis of it being a major route and very little else taken into account. Is there a resource to look up historic speed limits?