A27 Worthing and Lancing improvement

[Micro The Maniac]

An online bored tunnel for Worthing with Lancing surface bypass is also possible. TBMs have come a long way since 1992.

The South Downs National Park did not exist in 1992

[KeithW]

An online bored tunnel for Worthing with Lancing surface bypass is also possible. TBMs have come a long way since 1992.

The South Downs National Park did not exist in 1992

The other aspect was that the plan was part of the Roads To Prosperity project which was discussed here some years ago
viewtopic.php?f=1&t=26832

One proposal I recall from the time was to improve the A259 from Brenzett to Hastings which would have involved either a very expensive tunnel from Rye to Winchelsea or followed the line of the Marshlink Railway line across the Brede Valley. This as I recall brought forth a raft of protection measures including wildlife conservation zones recognizing Sites of Scientific Interest that lead to East Sussex County Council which had been given permission, and funding, to design the scheme abandoning the idea.

[jackal]

I think today there are only really 3 decent options:
1&2, very similar to the previously rejected red and blue routes, tunnelling under Cissbury Ring
A 3rd option could be going even further north, around Findon, to avoid tunnelling under Cissbury, then joining up with the eastern section of the blue alignment

Nither are viable... look at Arundel, which barely touched the South Downs National Park, and here you are proposing to drive a road through (even if under) it... and I'd love to be a fly on the wall at the National Trust when you propose digging under Cissbury Ring

You might have got away with that in the 1960s but not today!

Just to be clear, two of the 1992 proposals went near rather than under (!) Cissbury Ring, with tunnels as environmental mitigation.

Bear in mind that this NP isn't exactly an unspoilt wilderness, and includes entire towns as well as the M3 and expressway sections of the A3, A23, A27, and A34. If new housing estates (e.g., https://www.google.co.uk/maps/@50.99730 ... a=!3m1!1e3) and freeflow interchanges (M3 J9 rebuild) are okay then a bypass can't be ruled out. The legal standard is that there are no reasonable alternatives avoiding the park, and obviously there are no such alternatives at Worthing - they've tried the crappy at-grade options and they wouldn't fly. The golf courses and fields surrounding Worthing are in the NP, so even the most environmentally sensitive route with a tunnel under the town can't help but enter it either side.

[Truvelo]

Yeah, Cissbury Ring would probably be on the ideal line for a northerly route as both routes take a detour to avoid it. Looking at the length of the tunnel for the northernmost route and the second tunnel west of the A24 then I'm sure one long deep bored tunnel for an online route would come in at about the same length and the shorter distance of this route would make it very attractive indeed. I therefore wonder why this was never considered in 1992 as this option would please most parties concerned.

[jackal]

I'd guess the tunnels in the 1992 designs were cheaper cut and cover efforts, as was the Stonehenge design of the time.

[JammyDodge]

I think today there are only really 3 decent options:
1&2, very similar to the previously rejected red and blue routes, tunnelling under Cissbury Ring
A 3rd option could be going even further north, around Findon, to avoid tunnelling under Cissbury, then joining up with the eastern section of the blue alignment

Nither are viable... look at Arundel, which barely touched the South Downs National Park, and here you are proposing to drive a road through (even if under) it... and I'd love to be a fly on the wall at the National Trust when you propose digging under Cissbury Ring

You might have got away with that in the 1960s but not today!

I actually think the NT would be less of an issue with tunnelling under Cissbury, due the depth of the tunnels
The A24 is less than 50m above sea-level in Findon Valley, according to contours
That would put a tunnels portals at around 55-60m above sea-level (the top of Cissbury is ~160-180m), placing the tunnel at more than 100m below Cissbury
Which could make a tunnel like this:

However, I can still see this as being controversial, as seen with Stonehenge, with NT and EH, the land owners, supporting the tunnel, but other groups not

[jackal]

As mentioned sbove, one issue with a bore under Worthing is that you're picking up only a minority of the A27's traffic. A bypass can collect more due to the A24 GSJ.

[jervi]

Most people do not use the A24 to get to the A27 though, unless their destination is Worthing or Lancing. If people are going East then cut across to the A23 at either the A272 or A264, or if going West use the A280 (Long Furlong).
Of course a HQDC A27 at Worthing/Lancing would change this, but a junction between the A24 and trunk A27 isn't entirely required.

Also if there were a junction between the A24 and A27 then the A24 would have to be improved between the A280 Findon Roundabout and the new A27 junction. The A24 around Findon is horrid, recently lowered to 40mph dispite being a dual carriageway.

[KeithW]

I think Cissbury Ring is off the list of routes.

First and foremost its a scheduled ancient monument and the area around it contains a number of ancient barrows but worst of all from the point of a tunnel is that within the site are well preserved neolitihic flint mines and the surrounding area is full of archaeology from the iron age streatching through the Roman and early Saxon periods. The flint mines are at least 15 metres deep. To compound matters a number of points close by are listed as SSI's

The land is largely owned by the National Trust and is inalienable meaning a compulsory purchase order will not cut it. There was a previous attempt to build a road through the area which saw enough opposition that it was ruled out. Any idea that the NT and EH would support such a project is wishful thinking. Do recall that in the case of Stonehenge the tunnel would remove an existing road not cross a hitherto undeveloped historical site.
http://www.sussexarch.org.uk/saaf/cissbury.html
https://designatedsites.naturalengland. ... 004162.pdf

In the case of Hindhead Tunnel the NT took the view that building the tunnel was better than keeping the old A3 open but you had better also recall that the tunnel section came at a price of £155,000 per metre. Then there is the little matter om implementing a fire management and escape system if you have tunnels 50 to 100 m deep. You also need credible ventilation systems. Any way you cut it even if you could get the permissions this would be a VERY expensive project.

If you really want a tunnel then somebody has to take a hit and CP land along the A27, demolish properties , dig a cut and cover tunnel and reinstate it as a linear park.

[Fluid Dynamics]

I know the area and route well. A route across the downs was felt unacceptable 30 years ago and would not be built now. The cut and cover on-line scheme of the 90s would face massive opposition from those in High Salvington who bought up the previously CPO's properties. There is also an already vocal bypass not through pass movement. How you negotiate this is anyone's guess.

At the moment there is no Governmental appetite for significant costs associated with bored tunnelling with regards this scheme. This could change in the future if and when Chichester, Arundel and East of Lewes ever get built and the road takes on a more strategic role. For now if a scheme progresses, and Chichester shows that the Government is prepared to walk away if a consensus solution cannot be found, I think any scheme will try to deal with capacity, with limited widening of the existing route and junction improvements. The only junction I find that has significant queues is westbound at the retail park junction west of Sompting/Lancing. Providing some form of grade separation here and adding an additional westbound lane as far the A24 junction towards Findon would improve flow. I would not convert the two roundabouts either side of the A24/A27 multiplex as these work reasonably well, there's space at the western A24/A27 roundabout potentially for some form of compact grade separation, although the westbound A27 exit is quickly constrained by he cemetery to the north. All of these works are outside the national park boundary. The other junctions don't cause massive queues, are constrained by the national park boundary, and general aren't the problem.

[jackal]

HE already tried to do some online fiddling and got shouted down. The mainline capacity (largely S2) just isn't there to utilise GSJs, and it's unreasonable to add lanes and traffic on what are actually residential streets.

The bypass not throughpass people are off their rocker, with a route via Washington roundabout that would literally go in one side of the NP, out the other, and back again. Terrible environmentally, very expensive, and little use in transport terms.

It does show that there's support for the bypass concept, so maybe a dose of reality might make something like the 1992 bypass more acceptable. The fact it was rejected at an early stage in 1992 is neither here nor there really. Many routes get built that were rejected at one time or another.

The bored tunnel does indeed face significant disadvantages in terms of cost and connectivity, but it's the only option that's technically viable and has a good chance of public support (the bypass has an outside chance).

Alas, the horse I'd back is 'too difficult and expensive to do anything'.

[xnx]

This could be controversial but would having a tolled tunnel be an option from Lancing east to Worthing west to get it done? I cannot see the government just paying for it like the Hove tunnel that was done in a different era.There could be an option to have the toll until the contruxtion cost has been paid and the toll could be better priced than the expensive M6 Toll.

The A27 is just going to get worse with the new Ikealess roundabout getting built soon instead of something more sensible what I would call a thin gsj like the A3 at Roehampton that serves the Asda.

[jackal]

Little traffic is going from east of Lancing to west of Worthing.

Even if it was from one side of Worthing to the other there wouldn't be the demand as a high proportion of traffic is going to Worthing and much of the rest would shunpike. You can't fund a bored tunnel off 10k AADT or so (the projection was 20k AADT for an untolled bore).

[Phil]

This could be controversial but would having a tolled tunnel be an option from Lancing east to Worthing west to get it done? I cannot see the government just paying for it like the Hove tunnel that was done in a different era.There could be an option to have the toll until the contruxtion cost has been paid and the toll could be better priced than the expensive M6 Toll.

The A27 is just going to get worse with the new Ikealess roundabout getting built soon instead of something more sensible what I would call a thin gsj like the A3 at Roehampton that serves the Asda.

And what exactly is so sensible about a GSJ when the road smashes into the roundabout on the eastern edge of lancing a mere 800 yards or so further on!

[jackal]

NH have published a History of Larger-Scale Options report, as well as a summary leaflet:

https://nationalhighways.co.uk/our-work ... #documents

From a quick skim it seems this is mostly an effort to discredit larger scale schemes, though there is some interesting material, e.g.:

[ChrisH]

NH have published a History of Larger-Scale Options report, as well as a summary leaflet:

https://nationalhighways.co.uk/our-work ... #documents

From a quick skim it seems this is mostly an effort to discredit larger scale schemes, though there is some interesting material, e.g.:


A27 Worthing - Copy.JPG

The TfSE Strategic Investment Plan consultation discusses this, more by accident than design I think. On p92 of the document, in the Funding and Financing section, it gives a case study of highway schemes and mentions that National Highways plans to consult on options later in 2022 including a "long term" solution of a 4-5km tunnel.

[jackal]

Yes, I'd posted that in the TfSE thread:

A27 Long Term Worthing Solution
Description
The A27 through Worthing and Lancing is used
for local journeys but is also an important route
for long-distance traffic.
Despite some improvements along the route
in recent years, there are many long-standing
challenges around capacity, delays, journey time
and reliability, safety and environment.
As a result of these difficulties, traffic diverts away
from the A27 to alternative routes that are less
suited to high volumes. Additionally, bus and
active travel journeys are held up by congestion
in Worthing.
A number of options for the corridor have been
put forward, and National Highways plans to
hold a public consultation later in 2022.
A potential “long-term” solution is the construction
of a new stretch of road, much of which would be
within a 4-5km tunnel, potentially making it the
longest road tunnel in the UK.
For the purposes of the SIP, a cost of around £2
billion is assumed for this scheme, to be delivered
between 2045 and 2050, although this figure may
vary as it is highly dependent on detailed design,
especially if the solution were to involve a tunnel
which would have options for different lengths and
configuration (e.g. single or multiple bore).

The 4-5km tunnel is interesting. As NH didn't mention anything like that as a historical option, it may be something they've worked up for the consultation - though more to take the temperature on a long term (2040-50) aspiration rather than as a RIS2/3 proposal.

4-5km would be exactly right for a bored tunnel under Worthing only. The road through Lancing is not as bad, and would not need to be replaced - just one or two GSJ.

A challenging thing about a 4-5km tunnel is that through traffic makes up only 30%, so benefits are marginal relative to costs unless you have at least one junction with the A24. The 2001 option (see image in my previous post) resolved this by having a break in the tunnelled section and seemingly a GSJ on the Hill Barn Recreation Ground, which would go down like a lead balloon.

Alternatively a single carriageway tunnel is mentioned in the report, and wouldn't need intermediate junctions, though it has not been proposed historically.

[Phil]

Little traffic is going from east of Lancing to west of Worthing.

I'd argue that is precisely because the A27 is so crap!

If I'm heading west I take the A272-A24 then either the A280 or the A283-B2139-A29 instead of crawling through Worthing and I doubt I'm alone.

As NH note the A27 represents the only strategic east -west route across Sussex (other than using lots more fuel and adding to the congestion on the M25) and as such Worthing - Lancing is something that needs fixing properly rather than ignoring!

[jervi]

Of course this needs to be taken with a big pinch of salt, but those are the options mentioned in the Transport for the South East's Strategic Investment Plan's Options Assessments Report for the whole of the A27.

[A303Chris]

Option 6 is what I do now, A283, A24, A280, yes it's 14 miles compared to 7 miles, so twice as long but its twice as quick!