Time to put cars in their place – underground


The economy needs some big infrastructure projects. How about burying a few roads, asks Steve Webb

We have long been told that pollution causes thousands of premature deaths in cities. King’s College London estimates the annual number in London is 4,300 annually, but who are these people? Without their specific stories, the dry numbers are difficult to get emotional about.

The recent publicity surrounding the incredibly brave and tenacious mother of Ella Kissi-Debrah’s successful fight to get pollution stated on her death certificate threw rare light on the real plights of millions of people living close to busy main roads. As well as the widespread death and debilitation caused by traffic pollution, the dehumanising effect of noise, danger and just simple obstruction to walking is the principal downside of living in a big city.

But the car is here to stay. In 20 years petrol cars will start to become rare, but there will be millions of electric cars. In an only slightly more distant future, self-driven taxis will ferry people around. Logistical algorithms will control swarms of self-driven vehicles to suit the daily patterns of workers and leisure seekers. Small pod cars will carry multiple passengers on multi-stop journey routes derived instantaneously to suit individual destinations and traffic conditions. The traffic computer will direct cars through any roads that avoid congestion. There will be no more traffic lights, highly choreographed traffic will ceaselessly filter through crossroads in both directions without a single collision. Buses and tubes will be obsolete. But electric cars are not noiseless, they are not pollution-free and they can certainly run people over, so what can we do?

Let’s take London’s Westway as an example. This major urban artery is just one of many major roads that tear through our cities, blighting the lives of rich and poor alike as it winds though Notting Hill and Latimer Road. Built despite widespread opposition at the time, it caused the demolition of hundreds of houses, wrecking entire neighbourhoods. “Get us out of this hell! Rehouse us now!” was a banner draped on Acklam Road housing. Michael Heseltine was heckled when he opened it. The really shocking thing about the Westway is its audacity. Believing in a bright car-filled future, politicians, town planners and engineers pushed through a huge piece of social engineering that the government actually paid for.

So why can’t we be that audacious about removing it? Did we believe more in the car in the 1960s than we believe in removing the blight of pollution from our children’s lives now? We need a few good infrastructure projects post-Brexit and post-covid, so here’s a plan. Build a car tunnel under the Westway from Hanger Lane to Paddington. Suck the air out of the tunnel through a filter. Turn the Westway into a linear park or cycle routes, tennis courts and cafés.

Is this possible? Wouldn’t it cause immeasurable disruption and congestion for years as such a thing was built? Not necessarily. Road tunnels are very common. There are broadly two types: cut and cover, where a large trench is excavated and a roof built on afterwards, or a bored tunnel.

The first of these options would be massively disruptive. The Limehouse Link in the City of London was a cut-and-cover tunnel built in the 1990s, which cut a swathe of destruction through London’s Docklands for many years and was, at the time, one of the most expensive tunnel projects of its kind. Bored tunnels, on the other hand, can be driven in much the same way as tube tunnels, but unlike tube tunnels the infrastructure for a road tunnel is far simpler and less expensive (no stations for example). Tube tunnels are normally driven with a tunnel boring machine or TBM for short. These worm-like machines drive their way through the earth leaving a concrete tube in their wake. They need to be launched from some kind of portal or shaft, but once in the ground they do their work with no disturbance at the surface at all. In the case of the Westway, the tunnel could start at Hanger Lane and follow the existing roadway right up to Paddington.

How much will it cost? It’s difficult to compare the cost of tunnelling projects as they are all different. The Hindhead tunnel, a four-lane road tunnel driven under rural Surrey reportedly cost £155,000/m and was billed as one of the most expensive road tunnels. On that basis, one on the Westway would cost about £1.2bn. The Dublin Port road tunnel, a bored 2.6m road tunnel to Dublin airport, on the other hand, only cost £86,000/m. Of course, beyond the construction cost, the increases in land values adjacent to the removed motorway would be considerable. The public and economic benefit of the linear park would be substantial. The reduction in pollution-related illnesses would be huge.

And what about the park? At 7.3km long and 30m wide, such a park could wind through Acton and Notting Hill with cycle routes that soar across the elevated sections of the Westway in fresh air and a car-free environment. It would be a fantastic commuter route. And, of course, it could also have leisure facilities such as tennis courts, lawns and cafés.

The garden bridge proposal was due to create 336m of linear park of a similar width for £200m, with plans for closing the gates for corporate entertainment. And we’re just about to spend £2bn to protect tourists at Stonehenge from the inconvenience of traffic noise.

So why can’t we spend some money burying urban roads and letting our kids grow up in cleaner air?

This article was originally published on Building Design