A303 Phase 2 Upgrade

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Stevie D
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Re: A303 Phase 2 Upgrade

Post by Stevie D » Sat Sep 26, 2020 11:24

Jack wrote:
Fri Sep 25, 2020 21:50
But if the A303/A30 was upgraded to dual throughout and so eliminated the S2-related congestion and slowdowns, that would categorically be the faster route, no? The laws of physics suggest that eliminating congestion, the route with less miles will be faster.

Also, the M5-A358 route is much more than 10 miles longer - Google suggests Taunton is 28 miles from Exeter, which if you add the roughly 10 miles extra that you're on the A358 for to get to the A303 (both the M5 and A358 are almost straight lines on these sections and make very little distance towards London on their own, which does little to mitigate the extra miles), suggests that it's a nearly 40 mile detour. If we take off what little distance they do make towards London, it's probably about 30-35 miles. The fact that such a detour has a 'very little difference' in journey time is another testament to how bad a condition the A303/A30 is in and how much journey time would be slashed by a fully dual A303/A30 route from the M3 to Exeter.

I just think trying to make the A358 which is a big detour the main route over the direct route which unlike in said example does already exist is a 'use the M25 to get from Dover to Portsmouth' situation; it's bringing traffic onto a route that should never have to deal with said traffic and just unnecessarily adds to the traffic burden.
Yes, the at an equal speed, the shortest route will always be quickest. That doesn't mean that the shortest route between two points should be upgraded to 70mph. Where traffic on broadly similar routes can be consolidated onto a single road, that can be a more efficient use of limited funds than improving every single road.

The A358 between A303 and M5 is about 9 miles, and this road is already very busy and needs to be upgraded anyway, both the road and the motorway junction. From the A358 roundabout to the start of the Honiton by-pass is 15 miles, and traffic levels don't really justify dualling, even taking into account suppressed demand. The terrain means that the A358 will be significantly easier to upgrade than the A303, so it makes a lot more sense to improve the A358 and J25 in one big project, to cope with the bulk of the Exeter traffic as well as the Taunton traffic, than to have two separate projects, one of which is significantly more challenging and not actually needed.

I have no idea where you are getting your distances from, but they don't match up with reality. It is pretty straightforward to check what the difference between one route and the other is, and the answer is that A303–A358–M5 is just 9 miles longer than staying on A303.
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Re: A303 Phase 2 Upgrade

Post by RichardA35 » Sat Sep 26, 2020 11:29

Jack wrote:
Fri Sep 25, 2020 21:50
...>I just think trying to make the A358 which is a big detour the main route over the direct route which unlike in said example does already exist is a 'use the M25 to get from Dover to Portsmouth' situation; it's bringing traffic onto a route that should never have to deal with said traffic and just unnecessarily adds to the traffic burden.
It is necessary to actually understand the local situation and take on board the figures given earlier. The A358 is the "major" route even though it has only a "regional" linking function rather than the (nominally) strategic function of the A303 at this point. This far south west, a "London to somewhere" radial route loses the significance it would have closer to the capital and it becomes a link between regional towns. Unfortunately fewer people want to travel Ilminster to Honiton than Ilminster to Taunton and so the improvements are aimed where they give the best value for money.

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Re: A303 Phase 2 Upgrade

Post by someone » Sat Sep 26, 2020 12:49

Jack wrote:
Fri Sep 25, 2020 21:50
Google suggests Taunton is 28 miles from Exeter, which if you add the roughly 10 miles extra that you're on the A358 for to get to the A303 (both the M5 and A358 are almost straight lines on these sections and make very little distance towards London on their own, which does little to mitigate the extra miles), suggests that it's a nearly 40 mile detour. If we take off what little distance they do make towards London, it's probably about 30-35 miles.
It is a good thing you took off that little distance, as if Ilminster to Exeter via Taunton is 38 miles, and that is a detour of 40 miles, it would have located Ilminster -2 (minus two) miles from Exeter!

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Re: A303 Phase 2 Upgrade

Post by Peter Freeman » Sun Sep 27, 2020 09:10

Edit: post deleted.
Last edited by Peter Freeman on Sun Oct 04, 2020 13:37, edited 1 time in total.

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Re: A303 Phase 2 Upgrade

Post by jackal » Sun Sep 27, 2020 10:18

skiddaw05 wrote:
Sat Sep 26, 2020 00:01
To me getting the A358 upgraded (first) seems the logical thing to do. For a start there's far less of it to dual compared with the A303/A30
This is also an important point. As well as being only a third as busy and more environmentally sensitive, the route to Honiton is twice as long. It would deliver comparatively miniscule value for money and only makes sense from the perspective of sabristic route number completionism.

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Re: A303 Phase 2 Upgrade

Post by someone » Sun Sep 27, 2020 11:37

Peter Freeman wrote:
Sun Sep 27, 2020 09:10
My guess is the more obvious one: HE's thinking for that document was way ahead of us, and they'd already decided to upgrade A358 instead of A303/A30.
As the document is titled "Creating an Expressway to the South West: the case for the A303/A358 corridor," no guessing is required. But the plan to route long distance traffic via Taunton instead of Honiton was not a secret.

That Highways England case document came on the back of a Highways Agency "A303/A30/A358 Corridor Study":
We intend to upgrade all remaining sections of the A303 between the M3 and the A358 to dual carriageway standard, together with a new dual carriageway link from the M5 at Taunton to the A303, as part of a long-term commitment to creating a new Expressway to the South West.

We will also set aside funding for smaller-scale improvements to the A303/A30 section between Southfields and Honiton to improve safety and journey quality for road users recognising that large-scale improvements would be challenging given the protected features and landscape surrounding the route. This includes some small-scale work in the Blackdown Hills Area of Outstanding Natural Beauty, taking account of the environmental sensitivity of the area.
https://assets.publishing.service.gov.u ... eaflet.pdf

The full study for that brief leaflet can be found here:

https://www.gov.uk/government/publicati ... cal-report

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Re: A303 Phase 2 Upgrade

Post by JackieRoads » Sun Sep 27, 2020 11:44

jackal wrote:
Mon Sep 21, 2020 12:19
The RIS2 document listed "A303 Phase 2 upgrade" in the RIS3 pipeline. This was unclear as to which schemes were included.

A HE webpage now seems to confirm that, after Stonehenge and Sparkford are complete, there are five remaining schemes on the A303:

- South Petherton to Southfields
- Chicklade Bottom to Mere
- Wylye to Stockton Wood
- Cartgate Roundabout
- Podimore Roundabout

It doesn't strictly speaking say that these will all be delivered as part of Phase 2 (some could be 'Phase 3'), but the way it is presented makes that seem likely. While dualling the remaining sections is fairly obvious it is interesting to see that Cartgate and Podimore are still planned as standalone schemes.

Also of note is the A30 Chiverton being bundled with these ("A303 / A358 / A30 corridor improvements").

https://highwaysengland.co.uk/our-work/ ... rovements/
Cartgate and Podimore Roundabouts are being GSJ'ed?
How would it be possible to make fantasy maps?

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Jack
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Re: A303 Phase 2 Upgrade

Post by Jack » Sun Sep 27, 2020 12:20

There's too many people to quote so I'll make a general response.

I don't live in the area (as my location would tell you; last time I checked the A26 doesn't go to Somerset) so I'm not 100% on the distances and such. I'll admit that I wasn't aware the M5 made such an eastward movement, I was wrong on that one.

However, I can see how rerouting all traffic up the A358 is going to cause problems just from looking at the map, even as D2. J25 and the A358-A303 interchange are going to become serious bottlenecks for all traffic if we increase the A358s traffic quite significantly, especially in their current forms.

It seems like people are lacking self-awareness here: On the A229 improvement thread, numerous people were explaining why putting local and regional traffic on the same route causes problems. Now on this thread, numerous people are saying that's exactly what we should do with the A358. Even with the relatively short detour mileage, it very much is a 'use the M25 for [journey completely unrelated to London]' situation.

It seems like we're doing the very British thing of directing all forms of traffic onto the same route, and when it goes wrong, we'll be baffled as to why it didn't work.

By all means, upgrade the A358. I have never been against that. But don't upgrade it instead of the A303/A30, do it in unison to work towards a better network as a whole.
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Re: A303 Phase 2 Upgrade

Post by Bryn666 » Sun Sep 27, 2020 16:32

The A358 and A229 are not remotely comparable.

A229 AADT: 69,336
A358 AADT: 23,648

That's why people are saying the A229 needs separation of traffic types, and the A358 does not.
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Re: A303 Phase 2 Upgrade

Post by someone » Sun Sep 27, 2020 18:59

There is also pretty much nothing between Ilminster and Taunton. So it would not have traffic constantly joining and leaving at frequently spaced junctions, which are the problem with local traffic as discussed on the other thread.

I believe there are only two proposed intermediate junctions as part of the dualling that section of the A358; with the A378 and for Hatch Beauchamp. Other existing accesses would be disconnected.

Which will be a lot easier to do than on the A303, which has a lot of property and farm accesses between Ilminster and Honiton.

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Re: A303 Phase 2 Upgrade

Post by RichardA35 » Sun Sep 27, 2020 22:13

Jack wrote:
Sun Sep 27, 2020 12:20
There's too many people to quote so I'll make a general response.

I don't live in the area (as my location would tell you; last time I checked the A26 doesn't go to Somerset) so I'm not 100% on the distances and such. I'll admit that I wasn't aware the M5 made such an eastward movement, I was wrong on that one.

However, I can see how rerouting all traffic up the A358 is going to cause problems just from looking at the map, even as D2. J25 and the A358-A303 interchange are going to become serious bottlenecks for all traffic if we increase the A358s traffic quite significantly, especially in their current forms.

It seems like people are lacking self-awareness here: On the A229 improvement thread, numerous people were explaining why putting local and regional traffic on the same route causes problems. Now on this thread, numerous people are saying that's exactly what we should do with the A358. Even with the relatively short detour mileage, it very much is a 'use the M25 for [journey completely unrelated to London]' situation.

It seems like we're doing the very British thing of directing all forms of traffic onto the same route, and when it goes wrong, we'll be baffled as to why it didn't work.

By all means, upgrade the A358. I have never been against that. But don't upgrade it instead of the A303/A30, do it in unison to work towards a better network as a whole.
If it was only so easy as to look at a map and decide that junctions will be overloaded a lot of my industry would be out of a job and replaced by school leavers.
The fundamental first step to finding a solution is defining the problem fully. That is, looking at the particular issues to the area in hand not applying logic from other parts of the country where things are different. There are also rather more issues to look at than just the map.
We also have to remember this is the South West where traffic is sparse and money more so. Prioritising investment towards economic stimulus and development will mean it is biased towards those schemes that provide the most benefits year round linking towns in the region for employment reasons rather than towards the routes with seasonally inflated traffic figures carrying holidaymakers. For good reason, traffic counts are carried out in neutral months outside the summer peak or dip depending upon area.

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Re: A303 Phase 2 Upgrade

Post by Peter Freeman » Sun Sep 27, 2020 23:56

Jack wrote:
Sun Sep 27, 2020 12:20
It seems like people are lacking self-awareness here:
Uh?
On the A229 improvement thread, numerous people were explaining why putting local and regional traffic on the same route causes problems. Now on this thread, numerous people are saying that's exactly what we should do with the A358. Even with the relatively short detour mileage, it very much is a 'use the M25 for [journey completely unrelated to London]' situation. It seems like we're doing the very British thing of directing all forms of traffic onto the same route, and when it goes wrong, we'll be baffled as to why it didn't work.
Here we go again ...!

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Re: A303 Phase 2 Upgrade

Post by Richardf » Wed Sep 30, 2020 23:49

Truvelo wrote:
Thu Sep 24, 2020 00:18
This argument was made in 1975 when the government was considering a link from the A303 at Podimore to M5 J25 along the A372 and A378 rather than improving the direct route via Honiton. The report I have concludes that the COBA of the direct route is better and this route is 6 miles shorter and therefore the route via J25 be abandoned in favour of dualling the direct route. The current A358 proposals would be a lot more than 6 miles longer than the 1975 scheme and even back then it was admitted that a large proportion of the traffic would still go via Honiton. Is history about to repeat itself 45 years later?
The A372/8 route looks good on paper and 'cuts the corner' compared to the present A358 plan but wouldnt be easy to do given the limitations of the ridge the existing route runs along. I should have thought the environmental cost of that route would be pretty high too.
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Re: A303 Phase 2 Upgrade

Post by jackal » Thu Oct 01, 2020 08:35

Hmmm I wonder what the environmental (and hydrological...) problems with putting an expressway through the middle of the Somerset Levels might be?

Anyway, I'm pretty sure Truvelo isn't suggesting that now given the A303 is dualled from Podimore up to South Petherton, requiring much more construction on the 'shorter' route, which wasn't the case in 1975.

Still, the implied claim that the Blackdowns route is 'shorter' misses the crucial point that the main reason to upgrade the route is A358 traffic, because there's three times as much of it as there is A303 Blackdowns traffic. And the A358 is a damn sight shorter as a route between Taunton and Ilminster (or Yeovil, Dorchester, Bournemouth, etc) than the A303 Blackdown Hills!

Advocates of the Blackdown Hills improvement really do need to explain how this is supposed to relieve the A358, a vastly more important route than the A303 Blackdowns.

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Re: A303 Phase 2 Upgrade

Post by Richardf » Thu Oct 01, 2020 09:22

jackal wrote:
Thu Oct 01, 2020 08:35
Hmmm I wonder what the environmental (and hydrological...) problems with putting an expressway through the middle of the Somerset Levels might be?

Anyway, I'm pretty sure Truvelo isn't suggesting that now given the A303 is dualled from Podimore up to South Petherton, requiring much more construction on the 'shorter' route, which wasn't the case in 1975.

Still, the implied claim that the Blackdowns route is 'shorter' misses the crucial point that the main reason to upgrade the route is A358 traffic, because there's three times as much of it as there is A303 Blackdowns traffic. And the A358 is a damn sight shorter as a route between Taunton and Ilminster (or Yeovil, Dorchester, Bournemouth, etc) than the A303 Blackdown Hills!

Advocates of the Blackdown Hills improvement really do need to explain how this is supposed to relieve the A358, a vastly more important route than the A303 Blackdowns.
No I wasn't suggesting we do it now, however if you look at the state the A303 was in the 1970s it was feasible, in 1975 the Ilchester bypass would still have been in the planning phase and could easily have been redesigned to tie in.

The A372/8 route follows a ridge of higher ground so whilst there are settlements to avoid like Langport, it wouldve avoided the Levels in the most part.
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Re: A303 Phase 2 Upgrade

Post by Peter Freeman » Sun Oct 04, 2020 03:23

Peter Freeman wrote:
Sun Sep 27, 2020 09:10
Stevie D wrote:
Fri Sep 25, 2020 20:15
Micro The Maniac wrote:
Fri Sep 25, 2020 09:20
I note with interest, on re-reading the Expressway document, that the Expressway was A303/A358 to Basingstoke/Taunton not A303/A30 Basingstoke/Exeter!
Well, yes. Because Basingstoke is the nearest town to the start of the expressway route at M3 J8, and Taunton is the nearest town to the end of the expressway route at M5 J25. It doesn't run to Exeter, in just the same way that it doesn't run to London or Plymouth and so isn't called the London to Plymouth expressway, even though it may well become the recommended route for traffic making that journey.
Stevie, that's a rather obtuse explanation of HE's expressway nomenclature. My guess is the more obvious one: HE's thinking for that document was way ahead of us, and they'd already decided to upgrade A358 instead of A303/A30. It makes perfect sense. And I presume they have longer-term ALR plans up their sleeve for M5 J25-J29 in case that section becomes congested as a result.
Stevie D: my comment above is withdrawn, with apologies. I misunderstood your post. Re-reading, it makes perfect sense.

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Re: A303 Phase 2 Upgrade

Post by Chris5156 » Sun Oct 04, 2020 13:29

jackal wrote:
Thu Oct 01, 2020 08:35
Still, the implied claim that the Blackdowns route is 'shorter' misses the crucial point that the main reason to upgrade the route is A358 traffic, because there's three times as much of it as there is A303 Blackdowns traffic. And the A358 is a damn sight shorter as a route between Taunton and Ilminster (or Yeovil, Dorchester, Bournemouth, etc) than the A303 Blackdown Hills!
Indeed, and if - as expected - a dualled A358 will take some traffic off the A303 through the Blackdown Hills, then you have the result that the A303 is provided with some relief from its traffic load anyway. The reverse would not happen - the A303 being dualled would not provide enough relief to the A358 to resolve its traffic problems.

I’d like to see the A303 dualled throughout as much as anyone, but head over heart, the facts dictate otherwise. The argument for the A303 is mostly emotional rather than rational.

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Re: A303 Phase 2 Upgrade

Post by ryzzey » Tue Jan 05, 2021 23:14

I’ve noticed recently a large number of trees have been cleared around the Podimore roundabout on the A303 near Yeovil.

Does anyone know if this is in preparation for the upgrade to start?

I know this stretch of A303 and the roundabout were designed ‘future-proofed’ to be able to be upgraded to a grade separated junction and roundabout hence the large spaces between the carriageway and size of the roundabout.

Interesting that this work is taking place if the decision has been delayed.

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Re: A303 Phase 2 Upgrade

Post by jackal » Wed Jan 06, 2021 07:56

Maybe it's this upgrade at the services?

https://www.google.com/amp/s/www.somers ... 748705.amp

Or possibly a compound for the dualling scheme?

I very much doubt that they would start work on a GSJ without formally committing to the scheme! Though it is an interesting thought that that upgrade could go through quickly, without the whole consultation and DCO statutory process, similar to the current A69 upgrade, due to the future proofing.

There have been some updates on the dualling scheme. I'll post a link in the relevant thread.

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Re: A303 Phase 2 Upgrade

Post by jackal » Wed Jan 06, 2021 08:02

Local press article of interest to this thread.

https://www.google.com/amp/s/www.devonl ... 813299.amp

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