A358 Taunton to Southfields

[Richardf]

An announcement of sorts on this scheme

Somerset A358 dual carriageway plans revealed - http://www.bbc.co.uk/news/uk-england-somerset-39417548


For us here this is not new. We have known about it for years.

[A307Patrick]

I honestly think hardly any long-distance (ie London/South East to Devon/Cornwall) traffic will use this new road if it is built as above.

Given that its an extra 9 miles for them to use this route, it would have to be built as per the 2007 proposals to entice people off the A303/A30 via Honiton section, especially if those A30 improvements do go ahead.

Only local and commuter traffic eg Yeovil/Ilminster to Taunton and other South/North movements will really use the new A358.

Also, given the cost figures I've seen for this proposal, I'm surprised its not better.

[jackal]

I'm actually surprised how low the indicated scheme costs are:

Option 1 + NFS £257m
Option 8 + NFS £244m (the consultation option)
Option 8 + J25 £266m
Option 2A/2B £284m

This is pretty cheap for around 10 miles of new dual carriageway with 3-4 new GSJs. The working assumption (e.g. here, p. 208) had been £415m.

The useless roundabout junction with the M5 saves hardly anything - the cheapest freeflow option (1 + NFS) is only £13m more expensive. I expect the main 'savings' come from excluding the Southfields GSJ and discounting to 2010 prices.

[A307Patrick]

Sorry, it was the £415m I had in my head - I hadn't seen your numbers above. As you say, though, the savings through not having a proper junction with the M5 aren't that much as a proportion of the total cost.

[jackal]

Understandable as the cost is one of many pieces of crucial information omitted from the consultation brochure. Even the questionnaire contains more information than the brochure in one important respect, namely that the M5 junction would use a roundabout.

[Berk]

I'm actually surprised how low the indicated scheme costs are:

Option 1 + NFS £257m
Option 8 + NFS £244m (the consultation option)
Option 8 + J25 £266m
Option 2A/2B £284m

This is pretty cheap for around 10 miles of new dual carriageway with 3-4 new GSJs. The working assumption (e.g. here, p. 208) had been £415m.

The useless roundabout junction with the M5 saves hardly anything - the cheapest freeflow option (1 + NFS) is only £13m more expensive. I expect the main 'savings' come from excluding the Southfields GSJ and discounting to 2010 prices.

It seems like they want to all the benefits of the scheme away for want of a £13m GSJ.

Taking niggardliness to new levels. Even Scrooge would be embarrassed by this extreme penny-pinching.

It just completely undermines the whole rationale for the A358 scheme. HE might as well not bother if this is how they plan to do it.

(I am, of course, referring to the M5 GSJ. I'm sure Southfields will be looked at at a future date.)

[SouthWest Philip]

(I am, of course, referring to the M5 GSJ. I'm sure Southfields will be looked at at a future date.)

Actually, Southfields is just as bad in it's own way.

Given that the plan is, presumably, for the A303 to effectively be diverted to join the M5 at Taunton it would be far more sensible to bypass Southfields some distance to the north. By doing this you get the following benefits;

* Smoother mainline saving over a mile in overall distance.
* Shorter overall distance increasing attractiveness for through traffic.
* No need for expensive online widening, and associated traffic management, for over two miles on the A303 and A358.
* Ready made east facing slips in the form of the existing A303 approaching the roundabout.
* Ready made west facing slips in the form of the existing A358 approaching the roundabout.

[Richardf]

What concerns me is that however the A358 scheme is done, if the Ilminster bypass is not dualled as well, you will leave a dangerous single carriageway gap in the route. It is bad enough now when the existing D2 ends and the bypass takes you back to S2+1, and then from that to S2. Once built this will happen in both directions, creating not just speed and overtaking issues but a pinchpoint when 2 lanes go into one.

This issue aside, while its disapointing to see the scheme watered down, any D2 will be better than maintaining the status quo and will surely attract traffic from the A303/A30 route.

[NICK 647063]

So something I'm wondering is as this scheme is part of the A303 upgrade will the new road be numbered the A303? It's a bit of a strange upgrade as it's an upgrade of the A358 by highways England but the A358 isn't a trunk road, so it's clearly to bypass the A303 and A30 towards the M5 so it should in effect become the A303.

It does seem crazy upgrading this road to add 9 miles onto people's journeys and sending them onto the M5, I guess with the live traffic sat navs in new cars people will continue to be directed on the current road as it would take some speed to be quicker to do an extra 9 miles, i guess the current A30 and A303 route via honiton will be detrunked?

[jackal]

No, it won't be detrunked.

What concerns me is that however the A358 scheme is done, if the Ilminster bypass is not dualled as well, you will leave a dangerous single carriageway gap in the route.

Dualling of the Ilminster bypass is assumed to open in 2028 (see here, p. 63).

This is also, of course, why the arrangement at Southfields under the current scheme is pretty unimportant, as it will only be like that for five years or so. By contrast, the layout of the M5/A358 junction is likely to be permanent.

[Richardf]

No, it won't be detrunked.

What concerns me is that however the A358 scheme is done, if the Ilminster bypass is not dualled as well, you will leave a dangerous single carriageway gap in the route.

Dualling of the Ilminster bypass is assumed to open in 2028 (see here, p. 63).

This is also, of course, why the arrangement at Southfields under the current scheme is pretty unimportant, as it will only be like that for five years or so. By contrast, the layout of the M5/A358 junction is likely to be permanent.

Still a way off though, and every chance of being dropped again in the meantime.

Yes the tie in between the upgraded A358 and the M5 is the biggest concern. J28 barely copes as things stand, add in a fast dual carriageway without an alternative will be a nightmare. OK the junction could be altered to give the A358 priority, but unless local and long distance traffic is separated it will become a major bottleneck and probably negate any benefits of dualling in the first place!

[Berk]

(I am, of course, referring to the M5 GSJ. I'm sure Southfields will be looked at at a future date.)

Actually, Southfields is just as bad in it's own way.

Given that the plan is, presumably, for the A303 to effectively be diverted to join the M5 at Taunton it would be far more sensible to bypass Southfields some distance to the north. By doing this you get the following benefits;

* Smoother mainline saving over a mile in overall distance.
* Shorter overall distance increasing attractiveness for through traffic.
* No need for expensive online widening, and associated traffic management, for over two miles on the A303 and A358.
* Ready made east facing slips in the form of the existing A303 approaching the roundabout.
* Ready made west facing slips in the form of the existing A358 approaching the roundabout.

I agree. But in this case, not all of the Ilminster bypass would need to be dualled. I would propose a fork in the main carriageway, which would curve to the north-west - to meet the improved A358. The westbound curve towards Southfields roundabout needn't be improved - unless the rest of the (current) A303 is.

All these schemes and potential schemes do call into question whether any, or part of the roads need to be renumbered. For consistency's sake, I would suggest keeping the A358 number on the new (to be improved) road. And maybe extend the A378 on the old road from Ash Cross all the way to Taunton.

Though I would support 'flipping' the A30/A303 numbers. The argument that 'it's no longer important/they have equal standing' is no longer true. And I would argue that nearly major improvement scheme since the 70s has resulted in renumbering. The reason being to dissuade drivers from continuing to use the old route and move on to the new one.

[SteveA30]

Visited the consultation near Ilminster today. I had a friendly and helpful chat with someone from HE, who has seen this thread. Didn't think to ask his name though.
Anyway, it seems the whole of Countess to M5 is due for completion in 2028 and, site work should start in 3 years, on the A358 and Stonehenge (it came up). GS'd throughout eventually. Southfields rbt will remain until Ilminster bp is dualled then, GS'd. I suggested a straight line from A303 to A358, north of Southfields, which is an option apparently.

Re. the M5 junction. I suggested a freeflow loop for A358 to M5 n/bnd traffic, much like the one between M42 and M6 at Water Orton. He urged that I put that in the questionnaire, which I will. The new A358 heads south, due to a major development between Henlade P&R and the proposed route. He said there is no connection planned from the new junction into Taunton. The old A358 will be the local access route. If it is built as a rbt, the conflict between A358 west -M5 north and M5 north - A358 east would cause huge queues on the M5 off-slip, especially in summer, if A303 traffic is drawn to this route.

The loop I suggested would allow the other junction to cater only for M5 westward traffic, making the whole layout freeflow, for both flows at both junctions.

Meanwhile, the Ilminster Little Chef will close in December, I was informed by staff.

[boliston]

There is a good route map here with proper overlays so the exact route can be found in relation to buildings etc - I expect some people might not be too happy like the owners of the mount somerset country house hotel who will have a major road a few yards from the building

https://mm-evt.maps.arcgis.com/apps/web ... c623d49b91

[jackal]

The consultation has been paused until after the general election:

http://roads.highways.gov.uk/projects/a ... uthfields/

[A320Driver]

Seems a bit daft to me that consultation is suspended during an Election campaign. Or is it political, this is traditional Lib Dem heartland after all?

Either there is no change in government and the scheme continues, or a new government comes in and suspends/reviews it anyway!

[jackal]

The problem is that HE staff would be hesitant to answer questions at consultation events given possible legal ramifications.

[crowntown100]

Since the election is over, the consultation is now open: https://highwaysengland.citizenspace.co ... uthfields/

The closing date is the 16th July 2017. There will be another consultation event on Friday 30th June between 10am and 7pm at the Holiday Inn in Taunton as the earlier event in May was cancelled.

[jackal]

"Highways England chose 'cheapest and worst' A358 proposal": http://www.bbc.co.uk/news/uk-england-somerset-40519637

The FOI documents mentioned in the article are here: https://www.whatdotheyknow.com/request/ ... ing-664272

[Richardf]

So what exactly is wrong with the chosen scheme? Not sure about where and how it meets the M5, but otherwise it looks OK to me.

Alright it's been watered down from the scheme that was scrapped a few years ago, but let's face it that was a touch 'gold plated' and over designed for what is needed.

So why the big detour to reach the M5? Won't favour N-S traffic at all.