New Lower Thames Crossing

[jackal]

As I've said before, option 4 would be the start of an outer orbital, as you'd have a stretch of expressway up to the A127. It's also the only option with a decent connection (four level stack!) with the A13, which is the main thing to get right between the M25 and Thames.

[Scratchwood]

To me the M25 between the M11 and A13 does have extra capacity when compared to other sections, indeed the road itself is one of the best sections of the whole road, with its proper D4M, relative lack of junctions and lack of bodged twisty bits (unlike other sections where Ringways 3 and 4 were bodged together!).

The only issues are really the junctions themselves which are inadequate, and the sections leading up to the M11 and A13, and the latter will be bypassed by this new crossing

[jackal]

The M11-A13 isn't too bad now, but there will be a clear need for new capacity by the time the LTC is open (2030 or so) given traffic growth and the easing of the constraint the Thames currently provides.

Route 4 provides that extra capacity between the A13 and A127, as well as addressing three other big capacity constraints in the area - the A127 junction with the M25 (which would get freeflow slips), the A127 itself (which would be improved to modern D4), and the LTC/A13 interface (which is very circuitous for option 2, and is a bottleneck in the making for route 3). So it does four useful things the other routes don't.

[Bryn666]

It should still be a motorway...

[frediculous_biggs]

It should still be a motorway...

Is there any indication it won't be?

The plans for Option 4 had a LAR alongside the replaced bit of A127, from the M25 to where the LTC leaves. Surely that wouldn't be needed if the road was to be an A-road?

[jackal]

The design is for D2 without hard shoulders, implying all-purpose.

The LAR would be to take the numerous local accesses off the A127 mainline.

[frediculous_biggs]

I'm pretty sure there were hard shoulders, at least through the tunnel

[Glom]

Such a shame. Hard shoulders are the stuff of a lost golden age.

[si404]

So it does four useful things the other routes don't.

What it doesn't do, however, is provide a direct link between Tilbury and the M25, allowing the freight traffic to bypass Thurrock and Lakeside. Route 4 means much more expensive Junction 31 and A13 upgrades in the medium term.

Route 4 also serves LTC-Tilbury, Chadwell, etc traffic poorly. Route 3 isn't great, but at least makes some provision. And the junction on the A226 makes a mockery of the notion that this is a road not for local traffic.

[jackal]

So it does four useful things the other routes don't.

What it doesn't do, however, is provide a direct link between Tilbury and the M25, allowing the freight traffic to bypass Thurrock and Lakeside. Route 4 means much more expensive Junction 31 and A13 upgrades in the medium term.

Actually Route 4 is pretty good in terms of docks connectivity, with a fully freeflow route - certainly far better than HE's preferred Route 3, which as far as I can see would require an at-grade U-turn. Tellingly, Route 4 is also favoured by the Port of Tilbury:

http://www.thurrockgazette.co.uk/news/1 ... ng_stance/

So maybe I was underselling it...

[Chris5156]

I'm pretty sure there were hard shoulders, at least through the tunnel

The hard shoulders are a future third lane in disguise. They won't be built on the surface level parts, but tellingly I'm sure there has been a reference to other structures such as overbridges being built in such a way that a third lane could be added at a later date.

[jackal]

I'm pretty sure there were hard shoulders, at least through the tunnel

I've seen no official mention of hard shoulders in relation to this scheme at all, and many mentions of its dual two lane standard. The Scheme Assessment Report report suggests future-proofing the tunnel for future conversion to D3, and sabristi have extrapolated from that that it will have a hard shoulder in the tunnel.

In any event, it is very unlikely that a 2 mile long temporary hard shoulder will result in the entire 13 mile+ route being motorway.

[jackal]

A couple of titbits from Highways England's CEO:

1. 'We are committed to having the tunnel up by 2025 and need to start construction by 2020'.
2. 'One thing I would say is the two lane or three lane decision has not yet been made. At the moment it is two lane'.

http://transport-network.co.uk/Jim-OSul ... work/13842

[Glom]

I'm sure two lanes will be fine. And also a signalised flat junction at Colnbrook will work with intelligent lights.

[jackal]

It's very silly that they've planned the section south of the A13 to be D2, when it's projected to have 90k AADT by 2041. Hopefully the design we'll end up with will have D3 for that whole section rather than mere future proofing in the tunnel.

[Gav]

If they build this then id be looking at making a corridor from the M20 use part of the M2 the new tunnel and then run round towards the M25.

make it a relief route !

[roadtester]

Now the route has been announced:

http://www.bbc.co.uk/news/uk-england-surrey-39575467

A slightly tweaked Option C.

[Bryn666]

And already the local MP is being a NIMBY.

[Matthew]

Aside from the D2/D3 question and that I would prefer also to strengthen the link to the M20, I think this is the better choice. Expanding capacity Dartford just isn't feasible, so shifting traffic away from the bottleneck is far more preferable.

Certainly there's a lot of detail that needs to be ironed out, but from what I can see this gets my vote.

[Glom]

Yay for not piling everything into a single choke point where Godwinson can gun the Norman forces down with the heavy artillery he had.