Urban motorways in London

[ManomayLR]

Can we not just motorway the HQDC sections? Like the A3 near Walton-on-Thames is D3M and could easily make another part of the A3M.

If they changed A3 to a proper "M" motorway, would the number have to start with a "2" (for example M28), seeing as it is east of M3?

One possibility is to change A3 to M3, and then change M3 to M30.

AFAIK the numbering system is based on the main A roads not the main motorways

[KeithW]

An M40 link into Central London via the WestWay will have traffic off at various points before the end. The London M40 will feature VSL, MS4 signs verge mounted on the Western Ave and gantry mounted on the WestWay, the latter of which may be upgraded to D4ALR if traffic congestion increases.

The only question is the junction numbering.

Well some traffic does come off at the North Circular but I dont think Northolt or Harrow are great attractions in the morning rush and as someone who used the Greenford Road fairly regularly to get from Harrow to Reading or Oxford I know which way the traffic moved there on a morning and most of it was not heading to the north and west for which I was profoundly grateful.

[Owain]

Can we not just motorway the HQDC sections? Like the A3 near Walton-on-Thames is D3M and could easily make another part of the A3M.

If they changed A3 to a proper "M" motorway, would the number have to start with a "2" (for example M28), seeing as it is east of M3?

One possibility is to change A3 to M3, and then change M3 to M30.

AFAIK the numbering system is based on the main A roads not the main motorways

The motorway numbering system is completely separate from A-roads (excepting Ax(M) numbers, of course!).

If the A3 became a motorway, it would indeed have to take an M2x number. To me, the most sensible number would be M24.

[Steven]

AFAIK the numbering system is based on the main A roads not the main motorways

<insert sheesh joke here...>

PM: How the Motorways Were Numbered

Roaders' Digest - the SABRE Wiki:Classification

[WHBM]

Here's the plans for the 90s scheme. It contains a tunnel as well which must be purely for aesthetic reasons. All the side roads are closed to prevent them being used to gain access to the A406. All the property required for this scheme was purchased. Number 46 on the North Circular is an empty plot as this would have been a new local access road.

One of those properties purchased is the manky one whose image I posted above.

It seems that the North Circular was to be depressed, with the crossing Golders Green Road retaining its level. Even with the property purchase and temporary carriageways out at the site limits that would have been an incredibly tight site to do the excavation and construction, while maintaining any semblence of the current traffic flow on the A406.

I also wonder about ground conditions. The A406 here is in the River Brent valley, the river is right alongside the north side of the junction, Golders Green Road slopes down to the junction and the river on both sides, hence all the green strip just above the road alignment in the plan. I am aware that just along at Finchley Road junction, where the same applies and there are adjacent marshes, the water table was the key constraint in the junction design. Yet this design has the road being put down subsurface alongside. The occasional extreme flooding of the A40 Hanger Lane underpass (ever noticed all the M&E in there is up at roof level ?), multiple sump pumps notwithstanding, shows what can happen.

[Scratchwood]

Here's the plans for the 90s scheme. It contains a tunnel as well which must be purely for aesthetic reasons. All the side roads are closed to prevent them being used to gain access to the A406. All the property required for this scheme was purchased. Number 46 on the North Circular is an empty plot as this would have been a new local access road.

One of those properties purchased is the manky one whose image I posted above.

It seems that the North Circular was to be depressed, with the crossing Golders Green Road retaining its level. Even with the property purchase and temporary carriageways out at the site limits that would have been an incredibly tight site to do the excavation and construction, while maintaining any semblence of the current traffic flow on the A406.

I also wonder about ground conditions. The A406 here is in the River Brent valley, the river is right alongside the north side of the junction, Golders Green Road slopes down to the junction and the river on both sides, hence all the green strip just above the road alignment in the plan. I am aware that just along at Finchley Road junction, where the same applies and there are adjacent marshes, the water table was the key constraint in the junction design. Yet this design has the road being put down subsurface alongside. The occasional extreme flooding of the A40 Hanger Lane underpass (ever noticed all the M&E in there is up at roof level ?), multiple sump pumps notwithstanding, shows what can happen.

Great to see that plan Truvelo, being fairly local, even it's slightly confusing as the colouring and shading is slightly impressionistic

Yes, the site is incredibly narrow, to do that reconstruction AND still provide sufficient capacity on the A406 to prevent complete gridlock! The design reminds me of the East End Road underpass in Finchley, where the A406 is sent into a trench under the local road, and a green bridge provided to screen the A406 off. That green bridge is surprisingly effective.

The water table would surely have been an issue at that site. The loss of the local junction to the A406 would have been unpopular as well.

[Truvelo]

Wasn't the East End Road underpass planned around the same time as the Golders Green scheme? It could explain the similarity. The only difference is East End Road is on high ground rather than in a dip.

[thatapanydude]

Following on from the M40 thread, here is my plan to sort out London's roads and provide an alternative to trains for cross london journeys.

Blue are motorway routes which are of a D3/D4 standard with HS and DLR. Red routes are roads which should be upgraded to at least 50mph and be of a D2 grade separated (mostly, a few roundabouts in places where its not feasible for grade separation would be tolerated e.g. parts of the A312 and A2016) standard.

Tunnels would be built at hanger lane, henlys corner and bounds green to provide a free-flow journey from the A40 to the M12 and A13. Also a tunnel would be provided for the M1 from Cricklewood to Westfield.

Is still believe that the A2016 can take extra traffic generated, as flows over the thames will be shared across blackwall and silvertown. Also this part of SE London has the A2 and A20 in close proximity.

Whilst I'm realistic that London's road problems will never be solved via this, at least a road network like this can deliver benefits of moving traffic from East to West London & North to South East London without the need of the M25.

[Scratchwood]

Wasn't the East End Road underpass planned around the same time as the Golders Green scheme? It could explain the similarity. The only difference is East End Road is on high ground rather than in a dip.

Yes, previously the A406 climbed quite steeply to a fairly spacious roundabout with the East End Road, so creating a cutting was easy with I imagine little extra land needed really and no water table issues!

[Glom]

I think we've all gone through our crayonista phase.

[c2R]

I think there's definite space for some improvements - Henly's Corner, Scratchwood Link, Wood Green, East London River Crossing, as well as improvements through Erith all seem eminanly sensible to me - particularly if the roads were put underground....