A38 Case for Action

[Berk]

If a new bridge was built alongside the Tamar Bridge to replace the cantilevered lanes, could they be removed and the bridge reconfigured to provide a basic D2 arrangement?? Or would it have to stay 2+1??

Though again, I guess you would need to do the same with Saltash. Maybe restrict the A38 to trunk traffic only?? Not easy.

[jackal]

You could easily fit one carriageway of a D2 on the existing bridge. Not sure why you'd want to build a new bridge though as the existing one isn't the biggest constraint in the area.

[Berk]

Can the tunnel be duplicated?? Either way, new tunnel and bridge aren’t cheap.

[Pilgrim Dan]

There's no where for another bridge or tunnel to go in Saltash, which is why the bypass had to be a tunnel in the first place.

The "easiest" route for a new bypass would be to go off-route at St Budeaux and head up river, crossing the Tamar and rejoining at Carkeel. However, this would involve a viaduct through the China Fleet Country Club, a much longer bridge, demolition of houses, an old fort, football pitches and MOD munitions land.

[wrinkly]

I imagine that if the bridge already in place had been D2, the tunnel would have been made D2 to match, and perhaps this might have been less structurally problematic than the actual S3 tunnel was.

[Berk]

There's no where for another bridge or tunnel to go in Saltash, which is why the bypass had to be a tunnel in the first place.

The "easiest" route for a new bypass would be to go off-route at St Budeaux and head up river, crossing the Tamar and rejoining at Carkeel. However, this would involve a viaduct through the China Fleet Country Club, a much longer bridge, demolition of houses, an old fort, football pitches and MOD munitions land.

Perhaps, but I’m not sure that will fly. It might be easier to look again at building a second tunnel, and bridge.

At least you’d have D3, or D2M right from the start. Local traffic might simply have to use the A38 to cross the river.

Another problem is that you have both land, and river-based links to build. If you build the land-based bypasses first, then you create a massive congestion hotspot in the form of the tunnel/bridge. And the same if you build the bridge and tunnel before the bypasses are ready.

Ideally, you’d secure funding for everything (as soon as planning allows, at least they can all be examined in one go), begin the tunnelling immediately, then begin bridge-building, but delay finishing the tunnel until the bridge is at an advanced stage of construction. Then about a year later start the bypasses, and finish the tunnel at the same time.

As the Bodmin links are likely to require tunnelling, I’d also be looking to progress that as part of the first phase. That should give enough time for geological problems to be identified and fixed before main carriageways construction.

For all that construction, you’d definitely be looking at an NSIP, so you’d really want Government/HE funding as well.The Devon A38 improvements can wait for another RIS - you’d need to get the Cornish improvements finished first.

[jackal]

"A38 Trerulefoot - Carkeel safety package" was accepted as an RIS3 pipeline project. There's some info in yesterday's Cornish Times article: https://www.cornish-times.co.uk/article ... hyear=2021

See also a recent email from the project manager: https://www.saltash.gov.uk/edit/stuploa ... 551684.pdf

Though details of the scheme are yet to be developed, given volumes around 25k AADT it's hard to see any satisfactory solution other than dualling.

Cornwall Council and Highways England have a separate very small scale scheme to improve safety between Bodmin and Saltash - vegetation clearance, markings, cameras, and the like: https://www.cornwall.gov.uk/media/40975 ... -final.pdf

[Richardf]

Back in the day there were plans to dual the A38 between Saltash and Bodmin, or at least as far as Liskeard. I wonder what would have happened with the bridge and tunnel if that had been done?

[wrinkly]

Back in the day there were plans to dual the A38 between Saltash and Bodmin, or at least as far as Liskeard. I wonder what would have happened with the bridge and tunnel if that had been done?

I think it was just to dual the single carriageway gap between the roundabout with the A388 north of Saltash and where the dual carriageway restarts a mile west of Trerulefoot.

[jackal]

A new bridge was rejected a few years ago as it's considered that there's sufficient capacity already:

https://www.plymouth.gov.uk/sites/defau ... Report.pdf

The tunnel, likewise, is not much of a capacity constraint as a lot of traffic has exited for Saltash and the tidal flow system is quite effective.

The main change I'd like to see there is fully automated charging and get rid of the booths. The impression of congestion is largely because traffic has to crawl around the booths even if it's not using them. The roundabout thingy is not really necessary either - the bridge offices could be accessed from the local road network. The A38 should just run in a straight line onto the bridge, maybe with bus activated signals if really necessary but otherwise freeflow.

Other than that I think the main priorities are a third lane between Magadon and Forder Valley, and the Trerulefoot-Carkeel dualling.

[crowntown100]

Back in the day there were plans to dual the A38 between Saltash and Bodmin, or at least as far as Liskeard. I wonder what would have happened with the bridge and tunnel if that had been done?

I think it was just to dual the single carriageway gap between the roundabout with the A388 north of Saltash and where the dual carriageway restarts a mile west of Trerulefoot.

I've seen plans with a Preferred Route Announcment from the early 90's for dualling between what was the western end of Liskeard Bypass and Bodmin in the old archives at Redruth. I haven't had a chance to visit the new archives, but I wasn't allowed to take a copy in the old one. I'm hoping I can at the new centre. The route can also be traced on BGS Borehole scans, for those interested, as well as the route options for Trerulefoot to Saltash.

Personally, I think priority should go to the Liskeard-Saltash section as that is considerably worse to drive than through Glynn Valley between Bodmin and Dobwalls, which has seen several improvements to improve junctions and forward visibility, which the eastern section is missing. Even the dualling between Liskeard and Trerulefoot is grim to drive in places, I assume due to parallel dualling so that one carriageway gets very narrow in places.

[SteveA30]

Much of that section of A38 has had climbing lanes added on almost every hill. These hills are mostly short but steep and very bendy, making for a 'stimulating' drive in summer. Everyone rushes out to overtake a lorry or caravan but, if there are 2 slow vehicles and one pulls out to take the other, there is a scramble to get past it when it pulls back in near the top of the hill. There are regular instances of those spilling over the hatching as the road narrows. There can't be many roads now where 60's style white knuckle driving can still be experienced.

[Truvelo]

I've seen plans with a Preferred Route Announcment from the early 90's for dualling between what was the western end of Liskeard Bypass and Bodmin in the old archives at Redruth. I haven't had a chance to visit the new archives, but I wasn't allowed to take a copy in the old one. I'm hoping I can at the new centre. The route can also be traced on BGS Borehole scans, for those interested, as well as the route options for Trerulefoot to Saltash.

I've seen records for Liskeard-Bodmin in the archives catalogue but I gave up ages ago looking for Trerulefoot to Saltash as I couldn't find anything, not even the library catalogue either. As for photos, I've yet to visit an archive where it isn't allowed. Most charge but some are free.

[crowntown100]

I've seen records for Liskeard-Bodmin in the archives catalogue but I gave up ages ago looking for Trerulefoot to Saltash as I couldn't find anything, not even the library catalogue either. As for photos, I've yet to visit an archive where it isn't allowed. Most charge but some are free.

There used to be two records offices/archives until recently when they were combined into one purpose built site, so perhaps it will be easier to track them down. I wonder if Plymouth might have anything in an archive? As soon as I can get there post-lockdown, I'm planning on going!

[KeithW]

If a new bridge was built alongside the Tamar Bridge to replace the cantilevered lanes, could they be removed and the bridge reconfigured to provide a basic D2 arrangement?? Or would it have to stay 2+1??

Though again, I guess you would need to do the same with Saltash. Maybe restrict the A38 to trunk traffic only?? Not easy.

Why would you bother ? white paint is cheaper.

[Glenn A]

I agree that dualling the A38 is important, as it would do much to improve Cornwall's economy and improve journey times to Plymouth. I know it's not as important a tourist route as the A30, but still carries significant amounts of traffic and is dangerous in places.