A30 Honiton - Devonshire House Consultation

[crowntown100]

Following on from the A303 thread, I have been looking at what Devon CC have proposed for this section of the A30. It turns out they have some pretty well developed plans for it, including a Monkton Bypass.

Details here and here.

My personal favourite is the Orange Option, which is S2/1 throughout.

[Richardf]

This of course depends a lot on what happens with the HE A303/A358 plans further east. If that doesn't happen the local plan for the Blackdowns wont help much, if they happen at all since I am presuming the Blackdowns route will be detrunked and handed over to local authority control if the A358 upgrade happens.

Edit. Plus of course this section proposed is probably the easiest bit in Devon to do. A303 from Marsh to the A30 (the next bit) is the worst section and probably hardest to sort out and may well be left until last! Be interesting to see what they plan to do with it, especially the sharp bend.

Looked at the plans, look good, but a shadow of what was originally planned here. Not sure why such a big diversion around Monkton is needed for the Orange Route, unless its some kind of future prooing for a possible resurrected A35 eastern bypass for Honiton? The routing of the Monkton Bypass does bring the A30 closer to the A35, albeit with the steepest section of the ridge still in between!

[Fluid Dynamics]

My personal favourite is the Orange Option, which is S2/1 throughout.

I quite agree, and the orange route looks very high quality. But the danger is that if more long distance traffic follows this route, which is what Devon CC suggest on the slides, the this will just create another Ilminster, leading no doubt to full dualling at some point in the future.

The Achilles heal to the proposal is the Devonshire House A30/A303 which just looks like an accident waiting to happen. If this is not going to be a GSJ then a roundabout would be preferable in my opinion, with a bypass lane for northbound traffic continuing on the A303.

[Truvelo]

Looked at the plans, look good, but a shadow of what was originally planned here.

Indeed, the full dualling scheme can be found here towards the bottom of the document.

I agree with the last post about the layout of the orange route. Miles of alternating S2+1 isn't the best. At least it's better than the current crawler lane near Monkton where you're lucky to get past two cars before it finishes.

[SteveA30]

Orange is better, because it leaves the old road alone, meaning, when the new road does an 'Ilminster' as it is known, I can use the old road there, as I do through Ilminster.

The Devonshire junction would be ok, if it was just for A30 traffic, as hardly anything turns right out of the A30. However, directing the Stockland road rat run that way, will bring a lot more to the junction. East facing slips would solve that, then, rt turn A30 traffic could also go that way, by turning left and, doubling back.

[Sou'wester]

To be honest any improvement to this section of road is welcomed. Even a S2+1 will make journey times a lot quicker here. Less bends, no villages to pass through.

Orange looks less politically difficult to sell. Although I notice that this route would be curtains for the little chef near Honiton.

[crowntown100]

My personal favourite is the Orange Option, which is S2/1 throughout.

I quite agree, and the orange route looks very high quality. But the danger is that if more long distance traffic follows this route, which is what Devon CC suggest on the slides, the this will just create another Ilminster, leading no doubt to full dualling at some point in the future.

If they (HE/DCC) get it right, strategic traffic would be sent up the A358, leaving the A30/A303 for local traffic or for when there is an accident on the A358. There is enough local traffic to justify it.

However, this would be dependent on Southfields becoming a GSJ with priority to the A358/A303 and free flow from the A358 to and from the M5. That way it could be quicker than via the A30/A303.

Re: Devonshire House. I don't think the junction looks too bad myself. I'm not local though, so it could be a terrible design for the location.

[Richardf]

Interesting how in the original dualling scheme had Monkton bypassed to the west, but both these new plans bypass it to the east? What has changed?

Re Dualling: Common belief is that traffic levels currently don't warrant it but could it be that traffic levels are at this level because of the unimproved nature of the road, rather than not enough traffic going that way. If it was better quality road, maybe more would use it (In preference to the A358 and M5) and justify upgrading. Chicken and egg scenario really. Yes I can see if the road is improved to HQ S2+1 it will make it a more desirable route and levels will rise. Maybe not straight away but if the whole Blackdown section were the same standard then it will happen.

[Stevie D]

Re: Devonshire House. I don't think the junction looks too bad myself. I'm not local though, so it could be a terrible design for the location.

Given that similar layouts at Dolgellau and Crowland have been associated with a high rate of serious accidents, I'm not sure it's a good plan. I particularly don't like the give way line for traffic turning left off the main road ... with no island separation, there is a real risk of left-turning drivers not realising they are required to give way, as that is not the normal practice.

[Sou'wester]

I'm very much of the view and I may be alone in this, but if HE dialled the entire A303/A30 to Exeter. It would go some way to easing the 30 mile tailbacks on the M5 from J13 to J20 in summer.

Reason being is less people would decide to the use the M4/M5 route from the South East.

[c2R]

I'm very much of the view and I may be alone in this, but if HE dialled the entire A303/A30 to Exeter. It would go some way to easing the 30 mile tailbacks on the M5 from J13 to J20 in summer.

Reason being is less people would decide to the use the M4/M5 route from the South East.

I think that what will probably happen is that Devon will widen the A30 to S2+1 on this section. HE will probably dual the A303 and A358 route. However eventually the remaining section will probably be dualled along with the S2+1 section - so this new alignment will be a good first step....

[Richardf]

Can't see the section between Marsh and the A30 ever being dualled. Too much of an environmental hot potato. I think they will have trouble improving it as S2+1 given the terrain. That's probably why it's not being tackled first, even though it needs doing ASAP. Honiton to Devonshire House probably has the best chance of going ahead!

Of course completion of the whole Blackdown stretch depends on LA cooperation. Somerset needs to see the benefit of doing their bit for this to work.

[TimM3-A55]

If they go for the orange route wouldn't it be best to build it D2 rather than S2+1. It's already a whole new route with mostly under/over-bridges for side roads, the extra cost must be small for one more lane.

Have they missed a trick with the last underbridge, couldn't that be made into a basic junction with the link road to remove the right turn to say on the A30?

I'm very much of the view and I may be alone in this, but if HE dialled the entire A303/A30 to Exeter. It would go some way to easing the 30 mile tailbacks on the M5 from J13 to J20 in summer.

Reason being is less people would decide to the use the M4/M5 route from the South East.

Agreed, it would also provide a good back up in the event of an M5 shutdown. Doesn't happen often of course but when it does the idea often comes up.
The argument ageist is the M5 and A303/30 routes merge at Exeter anyway, however it's a lot easier to sort of 5 miles of ques than 30 miles. 5 miles of ATM or ALR is a possibility, 30 miles not a chance.

[wrinkly]

If they go for the orange route wouldn't it be best to build it D2 rather than S2+1. It's already a whole new route with mostly under/over-bridges for side roads, the extra cost must be small for one more lane.

Cost is not the reason it's not D2.

[jackal]

If they go for the orange route wouldn't it be best to build it D2 rather than S2+1. It's already a whole new route with mostly under/over-bridges for side roads, the extra cost must be small for one more lane.

Cost is not the reason it's not D2.

It is at least one of the reasons:

A dual carriageway solution was also investigated. However, the cost of this is significantly higher with an expected cost in the region of £32m per km, with a total cost of £640m for the full Honiton to Broadway route. As well as costing three times as much than the preferred solution, this would have a lower cost benefit ratio and would have a high detrimental impact on the environment.

The assessment found that a wide single carriageway could be expected to provide high value for money, with a Benefit to Cost Ratio (BCR) of 3.6, compared to a new dual carriageway route with a BCR of 1.6.

This is also a rejoinder to those saying that the whole Blackdown route should be dualled. 1.6 is a very low BCR. Dualling the A358 has a BCR between 6 and 10 (p. 29 here).

[DavidBrown]

The thing is the A30 there is very rarely actually congested - the main benefits of the scheme is that it replaces a very slow and outdated road. Dualling definitely isn't required if the A358 is to be dualled.

[crowntown100]

Hmm... This one has slipped past us. A modified Orange Route has been chosen for the scheme, including a GSJ for at Devonshire House! An actual GSJ! On a single Carriageway road!

Anyway. If you can get over that, the scheme looks pretty good tbh. WS2+1 throughout, one junction with the A30 at Devonshire House, mostly offline with the old road becoming an LAR. It actually looks like a well thought out scheme.

Details here.

Devon are pushing this for RIS2 and have sent it to the Secretary for State for his consideration, so hopefully it will go into the next program. We should hear in the next two years whether it has made it or not as HE are hoping to have the schemes in place by 2019.

(On a side note, it would be quite interesting to see what schemes are being pushed for RIS2. My guess is that the remaining A303 schemes will be put forward and I know the A30 at Crowlas is getting pushed by the local MP.)

[Richardf]

The way things are going this scheme looks more likely to go ahead than the A358 upgrade. If so then at least part of one route will be improved which while not ideal is better than nothing! Perhaps that's the thinking behind why Devon are pushing ahead with thier plans?

[jackal]

Nice find! Technically it is dualled at the GSJ, similar to the A68. Also, it looks like a compact GSJ, as you'd expect given the low traffic flows. But I agree, with three lanes grade separated throughout it's surprisingly impressive!

On a side note, it would be quite interesting to see what schemes are being pushed for RIS2. My guess is that the remaining A303 schemes will be put forward

HE themselves seem to be assuming that the M3-M5 expressway will be completed by 2028:

The way things are going this scheme looks more likely to go ahead than the A358 upgrade.

The A358 upgrade is a committed scheme, due to start construction in three years. Devon CC are hoping to get this into the program for 2020-25; there is presently no commitment from anybody to actually build it.

If so then at least part of one route will be improved which while not ideal is better than nothing! Perhaps that's the thinking behind why Devon are pushing ahead with thier plans?

The A30 will still be a major route into East Devon when the A358 upgrade is built. Hence Devon CC want it improved regardless of other plans.

[Fluid Dynamics]

Hmm... This one has slipped past us. A modified Orange Route has been chosen for the scheme, including a GSJ for at Devonshire House! An actual GSJ! On a single Carriageway road!

Anyway. If you can get over that, the scheme looks pretty good tbh. WS2+1 throughout, one junction with the A30 at Devonshire House, mostly offline with the old road becoming an LAR. It actually looks like a well thought out scheme.

Details here.

Devon are pushing this for RIS2 and have sent it to the Secretary for State for his consideration, so hopefully it will go into the next program. We should hear in the next two years whether it has made it or not as HE are hoping to have the schemes in place by 2019.

(On a side note, it would be quite interesting to see what schemes are being pushed for RIS2. My guess is that the remaining A303 schemes will be put forward and I know the A30 at Crowlas is getting pushed by the local MP.)

I do not recall the GSJ at Devonshire House being in the original documentation that was published when the consultation started so this is an improvement. However, I am surprised at the GSJ design as traffic travelling SW bound on the A30 will be made to cross the A30 NB traffic, which would seem to put the two significant A30 movements in conflict. I can see a conflict with the LAR but a trumpet would work better in recognising the flows. Otherwise a reasonable scheme and the GSJ a welcome addition.