Fresh from being the subject of an idea to move its pedestrians and cyclists below ground, London might now see the same happen to its motorists. New proposals would see a number of the city's roads buried. The aim is to create new space above ground and make the city greener and more pleasant.

The proposal was announced by Mayor of London Boris Johnson during a recent visit to Boston, US, where a similar project has taken place. The Central Artery-Tunnel Project (nicknamed the "Big Dig") saw Boston's existing six-lane elevated Central Artery replaced with an eight-lane underground highway.

According to the Massachusetts Department of Transportation, the Big Dig was the "largest, most complex, and technologically challenging highway project in the history of the United States." It is said to have significantly reduced congestion, improved the environment and led to regeneration above ground.

The Greater London Authority says that over 70 sites across London have been considered for the potential introduction of tunnels, fly-unders and decking, the renderings for some of which can be viewed in our gallery.

Among the suggestions, a fly-under has been proposed for the A4 in Hammersmith that would reconnect the town center with the River Thames. A mini tunnel has been proposed for the the A13 in Barking Riverside, meanwhile, on the basis that it could open up a significant amount of land for future development and reconnect parts of the local area.

Decking over a section of the A3 in Tolworth would create land for new homes and connect the area adjacent to the new Crossrail station with the rest of the borough. And the addition of decking or a mini tunnel to the A406 in New Southgate would also create space for new homes and connect the surrounding area to the new Crossrail station.

Elsewhere, there is discussion about a potential replacement for the London Inner Ring Road. Johnson believes that an inner orbital tunnel or two cross-city tunnels could help to deliver more efficient and reliable movement of vehicles around the city.

Transport for London will now work with local London boroughs to develop the proposal. Costs and funding options will be explored before the proposal is revisited in May of this year.

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