Big (tolled) dig for London?

The biggest tolled urban highway tunnel in the world?  Well certainly the most expensive if it were ever to be built.

That's what has been proposed for London - yes London, according to the Evening Standard. Now there isn't money to finance it, nor planning permission or any details.  It is, at best, a vision of what might be a good idea, primarily to get ring road traffic off of the at street level connected series of streets that currently form the congestion charge zone, and into tunnels.

The cost is mooted at around £30 billion (US$50.5 billion), which is eye-wateringly high, but reflects deep-bored tunnels and likely very expensive sites for entrance and exit points.  However, let's think about how it might work:

- Tolls 24/7 at revenue optimising levels. Should be little real concern about monopoly pricing here;
- Extend the London congestion charge zone out to the boundaries of this road, hypothecating net revenue to the new road (and charging by distance and time of day);
- Reallocating road space from parts of the inner ring road for other road users, but also parking and commercial use, raising more revenue;
- Recovering part of the increase in value from properties along existing roads seeing a significant reduction in traffic;
- Dedicating the tunnels to ultra low emission vehicles operating in semi-automatic formations, so that capacity is doubled;
- Using the tunnels to facilitate express bus services as well (London has few of those);
- Replacing fuel duty on London roads with a distance based charge reflecting capacity and demand.

I believe the idea has some merit, and I think arguments about local air quality may well have significantly dropped due to technology by the time this sort of road might be completed, but also technology will have significantly increased capacity on existing roads.  Claims it will just fill up with traffic would be countered by tolling, and given that central London traffic is growing again with the congestion charge, it may simply be that London road users would be willing to pay for a faster road at levels not seen in other cities.

It is certainly worth some more detailed scrutiny and a range of scenario modelling exercises, but I suspect it will be some years before this will come to any fruition.  Perhaps more realistic might be parts of the plan or a few strategically located tunnels to bypass major bottlenecks (from point 9 to 7 on the map for example, or 6 to 5).  It is radical for a city that has had no major new road capacity built since the 1990s with the controversial East Cross Route.

It's important to think about several dimensions to the idea which should mean thinking about it differently from past proposals, such as the previous ringway ideas for London.

- Fully electronic free flow tolling means that such a road can be priced to avoid inducing demand that exceeds capacity.  Indeed such tolling should enable higher charging of parallel routes, so that through traffic is taken off of existing streets.
- Ever lower emission vehicles should help address environmental concerns.  Having such a road provide discounts for such vehicles can help accelerate this.
-  Greater automation of vehicles, allowing more capacity on existing roads, but also increasing capacity of new roads enhancing their utility and closing the gap between rail and road based transport for urban capacity.

All of this is not in the short term, but plans for major highway projects like this are far from short term, and so should be developed with an eye to that sort of future and given the scarcity of land in London, identifying locations for entrance points to tunnels should be the priority because acquiring such land and gaining planning permission to use it for that purpose is going to be the number one issue (it isn't money that people will protest about).

Below is the network (in blue) of motorways/major arterial highways London would have got had plans in the 1960s been completed, which was for four ring highways to be built.  This is superimposed on what exists, as the only one that was built was the M25, combining parts of the third and fourth ringway.  It wold have meant an inner ring motorway, a second ringway taking the North Circular and extending it, and a third ringway linking up with the M25 at the northwest and the southeast, plus a few other new motorways (notably the M23 to the south, M12 to the east and M1 extended south).  Had it been built as planned, it would have had a brutalist impact upon the city in many locations, but the counter is that many town centres are blighted now by high levels of arterial traffic that would otherwise have bypassed them.

London, has the entire ringway motorway plans come to pass with a few additional radial routes.

Compared to that grand plan, below is what was actually built, besides the M25, only parts of other roads were completed, notably much of the North Circular was upgraded, the East Cross Route built to connect the Blackwall Tunnels to the North Circular and A2, and the infamous Westway and stub of a West Cross Route.  Much more detail can be found out about London Ringways on these websites, CBRD and Pathetic Motorways.  Of course the result of this is that it's far easier to get across north London than south London by road, and there is a dearth of river crossings east of Tower Bridge.

M25, A406, A12, A312, A40 - what little of London ringways that was actually built

The new London inner toll tunnel ring would look something like this, below, in addition to the current network.

London's main highways with a mooted inner city tunnel highway

So it would be different from what was originally planned, would feed off of existing arterials from the east and west, but is specifically designed to enable the existing street level ring road to be substantially altered in parts to accommodate more pedestrians, cyclists and buses, whereas previous plans were to add capacity primarily to relieve congestion, rather than also reallocate road space.

From a road pricing point of view, it represents perhaps a very expensive and grand version of what has already been done in Oslo.  Can pricing, the rise of ultra low emission vehicles and modern tunnelling create new roads in central London that enhance the environment and mobility?

I think it's worth looking at, but given I am resident here I've written a bit more background on the idea, since it is not entirely new.

Boston's "Big Dig" today generates a mix of views.  For some it was a grandiose waste of taxpayers' money which is an exemplar of what goes wrong when the public sector goes out of control with large politically driven projects, for some it is exactly the opposite of what urban transport projects should be, but for others it has, despite difficulties, proven to be a well utilised asset that has freed up urban land for redevelopment removing the blight of above surface highways from parts of the city.

In London, a cross-transport, business, community interest task force (the Roads Task Force) has come up with something a little less grandiose, but no less expensive (although perhaps more sustainable) in the form of an inner city tunnelled highway which would be tolled, to try to remove traffic from London's existing inner ring road, which itself is largely a signposted interconnecting series of streets that form the boundary to the central London Congestion Charge Zone. This follows on from far more modest, but still £3 billion costed plans to significantly improve intersections and corridors at sites around London.

The purpose being to remove traffic from it and surrounding streets to allow for more surface street space to be reallocated to bike lanes, footpaths and bus lanes, and to clear traffic from polluting built up areas.  Given that the mode share for cars into central London is low (10 %, compared to 48% for trips around outer London) it is about dealing with the remaining traffic, much of which comprises trucks, delivery vans, trade vehicles (e.g. plumbers, builders), taxis and residents' cars.

London has had a rather unfortunate history regarding the development of modern, grade-separated highways.   From excessively grand plans in the post-war period that would have seen up to five ring roads around the city, the rather cheap and brutalist design of the first part of one of them (Westway) caused such an uproar that almost all of the plans were abandoned- much to the delight of anti-road activists and property owners, but leaving almost all of the city with main highways going right through town and suburban centres.   

So major urban highway construction largely didn't occur in London after such grand plans were scrapped in the early 1970s.  This was tenable for a while, not least because until the 1980s, London's population was in decline.  Given there was spare capacity on the Underground and rail networks, growth since then was driven almost entirely by not driving.  London saw few major highway projects, with the key exceptions being the completion of the M25 ring motorway (which kept traffic that didn't want to go to London from entering London, and facilitated growth in outer London), parts of the half orbital (A406 North Circular) and most recently the East Cross Route improving access in east London partly across brownfields sites and linking the Blackwall Tunnel to the North Circular.  Other plans for new roads, including the "Western Environmental Improvement Route" (an attempt to remove through traffic on some west London roads with a new tunnelled corridor) proved too expensive and too controversial, with one of the main problems being concern that new roads would end at locations that could not handle the redistributed traffic.  Bear in mind this was an era when tolling anything but bridges and tunnel crossings, was not seen as feasible because technology wouldn't allow free flow tolls.

Whilst the image below gives you some idea of how elaborate and extensive the road proposals were, it also indicates how little actually got built.

Dotted line were planned major highways, rest are major highways or existing streets

Following that project, transport policy changed with the election of the Labour Government in 1997, which initially suspended all new uncompleted highway projects taking the view that "building more roads just generates more traffic", which was subsequently followed by changes in the governance of transport in London by devolving responsibility from central government to an elected Mayor and the newly created Transport for London (although the Mayor still was dependent to a significant extent on getting capital funding from central government).  In 2000, Ken Livingstone was elected Mayor, on a platform of introducing a congestion charge in central London.  Livingstone had been a local authority politician back in the 1970s who opposed the highway construction plans, and he also declared a new transport policy of not increasing highway capacity on any corridor, so that a handful of stalled plans to improve some sections of highway were cancelled or scaled back significantly.  Livingstone did support a new east London road crossing to connect an economically deprived suburb south of the Thames (Thamesmead) with the North Circular and A13 highways to the north, but this was cancelled by Mayor Boris Johnson, who defeated Livingstone in the 2008 election.

When the congestion charge was introduced it did  reduce car traffic into central London, but the effects beyond the charging zone were less clear, there were some reductions on key routes towards the centre, but a key part of the policy alongside the congestion charge was to reallocate road space.  Bus lanes, cycle lanes and widened footpaths, often for good reasons, saw road space for motor vehicles reduced, so the net effect on congestion and delays was far more limited.   Whilst that was sustained through the financial crisis and recession, the economic recovery has seen a growth in road traffic, which is as much about freight and taxi trips as well as cars, which causes some concern about what to do next.

The congestion charge is now double what it was when it was introduced, although taking into account inflation it is more like a 75% increase.  The zone was expanded towards the west, largely for political and practical reasons, rather than traffic management, and then dismantled for the same political reasons (in reverse).

To do more will require a different type of scheme.  That means either breaking London up into multiple charging zones and charging to enter each zone for a different price, or charging by distance, time of day and location.  The politics of either are probably too hard for now, but the reality is that London is not going to deal with traffic without some serious additional pricing.  Freight isn't going to move onto Crossrail 1 or 2 or any other new rail based public transport, and taxi numbers are not going to go down significantly.   On top of that, a growing population will mean more commercial vehicle trips by tradespeople, and more car trips overall, because public transport is not going to meet the needs of everyone everywhere always.

So there will be a need for more incremental highway capacity, and a need to price existing capacity more efficiently.  The Greens will argue against any new capacity, but in favour of charging to reduce road transport overall, others may argue that as long as new capacity is charged for and paid for by users, it's fine to add it as long as it is managed in a sustainable way.

So what will be the key issues that need addressing?

1. Pricing:  Whilst tolling the new road will be essential, it almost certainly can't pay for it on its own.  The only way it could possibly be paid for would be to take congestion charge net revenue, expanded out to the new road, and to charge for the use of the roads that are bypassed.  Of course this will affect demand, but if the impacts on the network are dramatic, in reducing congestion and emissions, and improving travel times, will it be a price road users are willing to pay?

2. Location: Let's be clear, the lines on a map are indicative only, and with perhaps the exception of the western end, are concepts.  Whoever lives near a location for a tunnel portal is likely to be unhappy, as those locations will have intersections that need to handle more traffic and land will need to be bought, in a location where the likely land costs for a portal site will be in the millions.  That is going to be by far the most sensitive issue.

3. Cost:  £30 billion is the estimated cost, which puts it as being twice more expensive than an additional airport runway at Heathrow, or half the cost of HS2.  Once tunnels are dug they are there forever, so depreciating that capital cost over say 90 years, may help get it in perspective, but it is undoubtedly a project on a scale that is eye-watering (although this has not stopped large rail projects like Crossrail proceeding, albeit at half the cost).

4. Future of road transport:  One word, automation.  In a future of ultra low emission vehicles that can largely or completely drive themselves, will this mean existing networks can have far more capacity than they currently do, reducing the need for new capacity? Or will it mean new roads like this present far more potent opportunities to shift large volumes of people and freight rivalling that of railways?  Given the timelines needed for such a new road, this will become more apparent over time.  The main advantage such a road presents is flexibility.

Roads are, after all, just corridors for access, and if technology means the differences between road and rail narrow, then does it mean a different future for thinking about urban transport?

So how does the plan compare to what was proposed before, and what exists now?

This was the plan for an inner city London ring motorway in dark blue, with the latest idea in light blue, as you can see the parallels are at the northeast and the West, with connections to key arterials from the east and west, although the old Ringway 1 route offered connections from south London to the east on the A2 and towards the now heavily congested Blackwall Tunnels:

London Ringway 1 and latest inner road tunnel idea

However, the new proposal is designed to relieve the designated inner ring road, which is a network of signposted streets that vary in width from 2 to 1 lane of general traffic in each direction (and often an additional bus lane).  This is depicted in black below and effectively forms the boundary to the congestion charging zone.  Could it be that this is extended out to the new ring road if it were ever built, or have two charging zones?

London inner ring road with inner road tunnel idea

Of course some have suggested there could be another idea, which is to complete Ringway 2, which may seem familiar to some as much of the North Circular Road is as planned.  Below is a depiction of what it would look like to have completed both highways, including a new east Thames river crossing, which is perhaps the only idea that survived south of the Thames.  The problem is that besides the river crossing, tolls could only realistically be applied on the southern section, which would raise issues as to why south London gets a toll road, but north London doesn't.

London Ringway 2, North Circular and South Circular Roads as complete highways

Of course north London didn't get a complete orbital highway, it got some parts improved, but with four parts of the North Circular Road incomplete, with resulting bottlenecks at the traffic light controlled intersections (with 3 lanes each way either side of these junctions). Some "low cost" improvements were made at Bounds Green and Henly's Corner to reduce delays, but they remain major bottlenecks.  Yet it is much better than the south circular route.  The North Circular can take 46 minutes to go 22 miles, a similar distance route across south London can take 1 hour 50 minutes.  That's the difference between having a largely grade separated multi-lane highway, and using urban streets, and that's what a new tunnel could address.  The time, fuel and pollution savings, even assuming some traffic growth, could be substantial.

London North Circular Road as built with key bottlenecks

The INRIX traffic survey indicates that congestion on London roads is among the worst in the UK, which indicates that with growing population, a range of wider measures need to be taken to address this.  So far, the key interventions have been the congestion charge zones, large capital expenditure on London Underground and railway networks, reallocating road space to bus lanes and cycle lanes were feasible and not adding road capacity.

What has been suggested is that with ongoing growth, given tens of billions of pounds of spending on new rail infrastructure, some new road infrastructure is needed to cope, even as the mode share of private motoring declines, simply because London's road network is inadequate to cope with the traffic that uses it.  In a future with pricing, with low emission vehicles and greater automation of vehicles, issues of induced demand, pollution and safety become much less of a barrier to expanding road capacity than they have been to date.

I'd suggest to address congestion means a mix of targeted improvements and wide scale charging, but the politics around both building new road infrastructure and charging for it, are extremely difficult.  To do both (and I don't think you can do either on their own and get optimal outcomes) requires some other big decisions to be made.  One being to purchase land for road improvements at considerable cost, the other is to take steps to allow partial replacement of fuel tax (EU law requires there to be a tax on fuel, albeit at a minimal level of around half existing levels in the UK).

Is the proposed tunnel the right solution?  I simply don't know, I'd suggest a lot can be done to fix existing intersections, to properly address bottlenecks like the ones in the map above and the like first, before new corridors should be built, but to investigate and plan for new corridors is wise, as is preserving options for land that may be used for this in the longer term.  Mistakes have been made in the past to waste opportunities to do this (e.g. a long mooted third new Blackwall Tunnel is now almost impossible thanks to building permission having been granted to high rise buildings directly above the most practical route - these sorts of mistakes should be avoided).

Could new tolled highway infrastructure, in tunnels, help in London?  I think, if managed properly, the answer is yes.  Are they economically efficient to build?  That is far from clear, but it doesn't help to think about them without thinking about where technology for road transport is heading, which may significantly change the answer to that question.