A12 Chelmsford to A120 Widening Scheme

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JonB2028
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Re: A12 Chelmsford to A120 Widening Scheme

Post by JonB2028 »

jackal wrote: Tue Aug 20, 2019 09:37 While that seems a reasonable idea, it's sad to see a discredited pinchpoint-style signalisation being proposed before either road is even built!
Agree, certainly on the east side of the junction I can see no reason why a trumpet arrangement wouldn't work. Maybe someone has an irrational dislike of loops, thinking they are dangerous?

On the west side looking at the ECC video for A120 it's more complicated. If the junction were simply between the new A120 and the A120 then a standard trumpet would work, but if you then try and provide connections to the existing A12 - and quite a lot of traffic from the new A120 likely wants to use it to get to Witham - it gets more complex and the lack of room to the railway presents challenges.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by jackal »

JonB2028 wrote: Tue Aug 20, 2019 19:43
jackal wrote: Tue Aug 20, 2019 09:37 While that seems a reasonable idea, it's sad to see a discredited pinchpoint-style signalisation being proposed before either road is even built!
Agree, certainly on the east side of the junction I can see no reason why a trumpet arrangement wouldn't work. Maybe someone has an irrational dislike of loops, thinking they are dangerous?

On the west side looking at the ECC video for A120 it's more complicated. If the junction were simply between the new A120 and the A120 then a standard trumpet would work, but if you then try and provide connections to the existing A12 - and quite a lot of traffic from the new A120 likely wants to use it to get to Witham - it gets more complex and the lack of room to the railway presents challenges.
There's loads of space between the A12 and the railway. The preferred route just had an offslip diverging a ridiculously long way to the west, a whole km away from the A12: https://youtu.be/19HCIJlCifE?t=319

This is my suggestion from a while back superimposed on the preferred route (click to expand):

A12 A120 - Copy.jpg
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Re: A12 Chelmsford to A120 Widening Scheme

Post by JonB2028 »

Looking again at the news articles, the A12 realignment HIF bid is not one of the ones for which funding was announced https://www.transport-network.co.uk/Jav ... ners/16093
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Re: A12 Chelmsford to A120 Widening Scheme

Post by jackal »

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Re: A12 Chelmsford to A120 Widening Scheme

Post by jackal »

The preferred route for J23-J25 has been announced, so there is now a preferred route for the whole J19-J25 scheme:

https://highwaysengland.co.uk/our-work/ ... ng-scheme/

The route will be D3 throughout, mostly through online widening but with offline sections at Rivenhall End and between Kelvedon and Marks Tey. Three GSJs (J20a, J20b and J23) will be removed, the one at Rivenhall is bypassed, and the remainder will be reconstructed. It seems a good idea to remove J23 as it should allow the proposed A120 to join there at a purpose built freeflow junction rather than be bodged onto a roundabout.

As we've come to expect from 'full' widening schemes costs are extravagant at £1.045bn. Even so full lane width is not quite maintained throughout as the existing River Ter bridge is retained and the scheme no longer includes reconstructing the J19-20a carriageway, which is D3 already.

The SAR addendum provides some useful detail: https://highwaysengland.citizenspace.co ... dendum.pdf
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Re: A12 Chelmsford to A120 Widening Scheme

Post by BF2142 »

Why do HE need to wait until 2021 to start another public consultation? Why can't this route announcement be the consultation? Give people a month to comment, then get the planning application in.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by Runwell »

If J23-25 is going to be kept online, I wonder if they will finally overhaul the awful concrete surface across the Kelvedon bypass, which is crumbling in parts? If M25 projects are anything to go by, don't hold your breath.

J19-20 northbound is already a congestion hotspot in the evening, largely due to lane 1 going off to Hatfield Peverel, causing a lot of last second weaving, for a junction that sees very little traffic exit. Even the addition last year of a new ADS one mile from the junction hasn't made much difference.
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Re: A12 Chelmsford to A120 Widening Scheme

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The Preferred Route anouncement for the A12 shows a new junction between Kelvedon and Tiptree. If this is built it should be possible to join the B1023 (Inworth Road) and access Tiptree without having to drive through Kelvedon. There are other interesting features including no junction 23 for Kelvedon meaning traffic would have to exit the A12 at the new junction 22 and use what will become the old A12 through Rivenhall End to access Kelvedon (village). It looks like a new junction 23 would only get built when the proposed A120 (link to the A12) is completed, also it looks like all of the preferred route for the A12 between the new junction 24 (B1023 exit) and the existing junction 25 will be constructed offline of the existing dual carriageway.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by Runwell »

I presume any new link road off the A12 between Kelvedon and Inworth will have to involve Hinds Bridge being replaced, which causes a traffic conflict at the moment?

J24-25 was an online upgrade, with a number of farmhouses still fronting on to the A12. By-passing this section and likewise at Rivenhall will at least finally clear the last sections of this nature.
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Re: A12 Chelmsford to A120 Widening Scheme

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roadphotos wrote: Wed Sep 02, 2020 16:07 There are other interesting features including no junction 23 for Kelvedon meaning traffic would have to exit the A12 at the new junction 22 and use what will become the old A12 through Rivenhall End to access Kelvedon (village).
Correct. The old A12 will remain dualled up to the fire station, where there will be a rbt. The bypassed GSJ at Rivenhall will be kept. The short section north of the fire station linking to the B1024 will be reduced to S2.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by Bryn666 »

Presumably "we aim to improve walking/cycling/horse riding" means they'll be doing something more than just a token path along the bypassed bits.

The A12 suffers from piecemeal syndrome with all the various bypasses being built to a slightly higher standard than the online dualling between them. Hopefully this work will bring some sort of consistency between the M25 and the exit for Harwich but I won't hold my breath yet.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by jackal »

Here's J22 and LAR:

A12 LAR - Copy.jpg

Also J24:

A12 J24 - Copy.jpg

The J24 dumbbell was initially planned to be directly on Inworth Road (option D) but Vissim told them S2 would queue between the roundabouts, and D2 would require the A12 bridge to be demolished. What they've come up with is an abomination though. As they admit, it will only be 1.2km from the future A120 junction, so given likely traffic flows will require widening of the just-widened road or (more likely) a departure. They don't seem to have looked into making the link between the option D roundabouts S2+1, which should fit under the bridge.

As an aside, this is pretty low profile for a £1bn+ scheme!
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Re: A12 Chelmsford to A120 Widening Scheme

Post by roadphotos »

It's certainly good to see that a new junction 24 is proposed to improve access to Tiptree via the B1023, I always thought that this should have been done when the original A12 Kelvedon by-pass was constructed. I always thought that it was crazy that all traffic from the A12 had to go through Kelvedon (village) before going under the A12 to Inworth and Tiptree. The other notable thing is that both Hatfield Peverel junctions are to go. Traffic will have to exit via the new junction 21 at Witham (south) and use a local access road to the village. I think it's a shame though that access to Maldon won't be improved. Ideally there would be a link road from the new junction 21 at Witham (south) that by-passes Hatfield Peverel and joins the existing B1019 to Maldon. When you consider all the new houses that are currently being built on the outskirts of the town you would think that at the very least there would be a plan to do this.
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Re: A12 Chelmsford to A120 Widening Scheme

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Bryn666 wrote: Thu Sep 03, 2020 13:08 Presumably "we aim to improve walking/cycling/horse riding" means they'll be doing something more than just a token path along the bypassed bits.

The A12 suffers from piecemeal syndrome with all the various bypasses being built to a slightly higher standard than the online dualling between them. Hopefully this work will bring some sort of consistency between the M25 and the exit for Harwich but I won't hold my breath yet.
It's worse than that for NMUs - in many places the footpath/bridleway crossing is just severed with no alternative provision made - while in other places you get to wander across the carriageway, if you dare. The whole A12 is an exercise in the sort of shambolic piecemeal road building approach that the UK has followed, and is the epitome of where we are today, with roads like it, the A1, A3, A34, A43 et al. performing these bizarre strategic functions while also serving as property accesses, and the only route in and out of some small settlements.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by Glenn A »

The A12 from London to Ipswich should have been considered for widening and possibly to a D3M as early as the Roads To Prosperity era. I've not been in this part of the country since 1988, but even then the A12 was becoming very busy and serving towns that were expanding with high car ownership levels. The section from Chelmsford to the A120 being upgraded is long overdue, as this has some poor D2 sections, but the whole road to Ipswich should be upgraded.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by owen b »

Glenn A wrote: Sun Sep 06, 2020 18:27 The A12 from London to Ipswich should have been considered for widening and possibly to a D3M as early as the Roads To Prosperity era.
Roads to Prosperity included big upgrade plans for the A12 :
new D2M from the M25 to Chelmsford
D3 for Chelmsford bypass
D3 for Hatfield Peverel to Witham
and beyond Ipswich :
D2 for Wickham Market to Farnham
D2 for Saxmundham to Lowestoft
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Re: A12 Chelmsford to A120 Widening Scheme

Post by jackal »

Glenn A wrote: Sun Sep 06, 2020 18:27The section from Chelmsford to the A120 being upgraded is long overdue, as this has some poor D2 sections, but the whole road to Ipswich should be upgraded.
Well, back in 2015 they did plan to widen it to D3 from the M25 to Chelmsford, and from Chelmsford to north of Colchester. Then finances got in the way. 2015 planning had Chelmsford to A120 at £100m-£250m; it's now projected to be 5-10 times higher (£1.045bn-£1.268bn).

It's hard to justify such extreme expense (£100m per mile) to merely add an extra lane to an already grade separated road. This is the same thing that killed the motorway widening programme. The problem here is that there's no cheaper alternative like ALR. So they've basically given up on M25 to Chelmsford and Colchester bypass widening, and similar schemes like A34 widening, none of which are even in the RIS3 pipeline.

I think Chelmsford to A120 is still justified given it has property accesses and LILOs (the same applies to A1 Darrington to Redhouse). My next picks would actually be J17-19 at Chelmsford and J27-29 at Colchester as they're very busy, pretty short and relatively easy to upgrade. But I don't really see a compelling case for M25 to Chelmsford; there are better ways of spending £1bn.
Last edited by jackal on Mon Sep 07, 2020 10:34, edited 2 times in total.
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Re: A12 Chelmsford to A120 Widening Scheme

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jackal wrote: Mon Sep 07, 2020 09:41
Glenn A wrote: Sun Sep 06, 2020 18:27The section from Chelmsford to the A120 being upgraded is long overdue, as this has some poor D2 sections, but the whole road to Ipswich should be upgraded.
Well, back in 2015 they did plan to widen it to D3 from the M25 to Chelmsford, and from Chelmsford to north of Colchester. Then finances got in the way. 2015 planning had Chelmsford to A120 at £100m-£250m; it's now projected to be 5-10 times higher (£1.045bn-£1.268bn).

It's hard to justify such extreme expense (£100m per mile) to merely add an extra lane to an already grade separated road. This is the same thing that killed the motorway widening programme ...
There really should be an attempt to identify what it is that causes this ballooning of estimates, the reason for it happening never being presented in detail. If a mainstream contractors' estimating department worked like this they would be out on their ear, if the business had not first gone under.

Not everything will have gone up by this huge factor, which means some elements have gone up by even more.
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Re: A12 Chelmsford to A120 Widening Scheme

Post by Bryn666 »

All those stupid and unlawful traffic management "innovations" like green cones and "my daddy works here" signs must cost a fair whack. Or at least they will when one is crashed into and it ends up in court.
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Re: A12 Chelmsford to A120 Widening Scheme

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WHBM wrote: Mon Sep 07, 2020 10:15 There really should be an attempt to identify what it is that causes this ballooning of estimates, the reason for it happening never being presented in detail. If a mainstream contractors' estimating department worked like this they would be out on their ear, if the business had not first gone under.

Not everything will have gone up by this huge factor, which means some elements have gone up by even more.
I don't know how they're getting costs an order of magnitude out, but there's certainly something going wrong in the estimates HE is working to, and at several points along the line.

For example once optioneering is done, we've found the initial cost is insufficient to cover the number or type of GSJs originally proposed, so junctions get dropped or changed to become compact GSJs, with all the attendant problems of safely tying in local roads. Then at detailed design problems with, say, visi may mean the alignment has to change, which in turn puts the design outside the red line boundary, so either additional land is required or something fancy needs to be done with the earthworks - both options obviously costing money. And this isn't about gold-plating schemes, it's only providing the minimum the scope requires. Design side the problem appears to me to be down to rushed or immature scheme designs being passed to the next stage, but there's also the degree to which the estimators are pinning down costs way too early, before all the risks have been identified never mind addressed.

I think all the RIS 1 and 2 schemes we've worked on the scheme costs have been underestimates, enough to leave experienced engineers scratching their heads as to how to get a conforming design to match them. Of course, it doesn't help that HE have this predilection to move schemes from consultant to consultant (all on the same framework) at each design stage, so all the accumulated knowledge developed by one team has to be re-learned by the next.
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