Cars. People love cars, don’t they? Matt Le Blanc loves cars so much he’s the new presenter of Top Gear, even though he’s American. Boris Johnson, meanwhile, loves them so much that he wants to bore enormous great holes under London to put them in.

Cars are great, aren’t they?

The latest wheeze from London’s soon-to-be-former mayor would involve two tunnels under the city, to connect the trunk roads that tail off in the city’s outskirts. The Northern Cross City Corridor would link the A40 at Park Royal in the west to the A12 at Hackney Wick in the east. That’s a distance of about 17.6km as the crow flies; but the proposals show the route going out of its way to connect with White City, so the tunnel, if built, would be rather longer.

Image: TfL.

A second tunnel, which is not currently named but would, let’s face it, be the Southern Cross City corridor, could link the A4 in Chiswick to the A13 in Beckton. That would be about 23km, even if the tunnel didn’t go via Oval and the Old Kent Road, which this one would. It’ll be a long tunnel.

All this is part of a package of measures outlined in a report published by the mayor’s office and Transport for London (TfL) this morning, and it’s a measure of the authorities’ keenness that all this seems suspiciously familiar. In 2013, in fact, the mayor was already proposing a huge underground ring road, which would have done a chunk of these routes. That popped up the following year, too.

 

Image: TfL.

Another version of the plan, revealed following a Freedom of Information request from the late and sadly missed blogger Tom Barry (“BorisWatch”) would have looked like this:

Boris Johnson leaves office in three months’ time. Even in the most optimistic assessments, none of these projects could possibly be ready for 20 years: they’re not going to be part of his legacy.

So one obvious reading of the fact they keep popping up would be that TfL really, really want them.

Today’s report claims that the new tunnels would reduce congestion by 20 per cent and save London’s economy up to £1bn a year. The press release contains this rather scary assessment of what will happen if we don’t start building massive pollution holes under London:

“If left unmanaged, congestion could potentially increase by 60 per cent over the next 15 years in central London, 25 per cent in inner London and 15 per cent in outer London unless these strategic plans are put in place.”

Hesitant as I am to doubt the words of my betters, I’m not really buying that. There is such a thing as induced demand: building more roads often encourages more journeys, and so doesn’t reduce traffic at all.

And it’s easy to see how that would happen here. At the moment, if you want to get from Romford to Uxbridge, or Hounslow to Bexleyheath, it probably makes sense to go the long way round, via the M25 orbital motorway. Build fast, crosstown tunnels, though, and the direct route will become a lot more attractive. Those tunnels will fill up, fast.

The clever people down at TfL must know this. So why are they so keen?

Perhaps they’ve fallen victim to the widely documented phenomenon in which Transport agencies over estimate traffic growth, and are panicking about the network’s capacity to handle it.

Or possible they just genuinely think that making it possible to cross town underground will reduce traffic above it.

If that’s true, it would fit nicely with another part of the plan (also a repeat from earlier announcements): putting existing trunk roads in tunnels where possible to free up land for other uses.

This bit of the plan is actually rather a nice idea. Sticking 1.3km of the A13 in a tunnel, as TfL is suggesting, would not only release land for 5,000 homes: it’d also end the situation in which Barking Riverside is cut off from Barking town, making it easier to regenerate both of them.

Perhaps, by the same logic, building the Northern  Cross City Corridor is an indirect way of putting the Euston Road in a tunnel, to generate some of the same effects.

But there’s on big question hanging over this plan. Tunnels need ways for cars to get into and out of them, and those portals take up space. It’s not obvious where you’d put the access point for the northern tunnel at Highbury Corner, for example.

This plan may free up some land for development – but it’ll almost certainly require demolitition of inhabited areas, too.

You can read more about this on the Mayor of London’s website, here.

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