Not only will it reduce blood pressure and incidents of road rage, the two east-to-west tunnels will save London's economy £1bn each year, the outgoing mayor and MP of Uxbridge argues.
Transport for London has been tasked with carrying out detailed feasibility studies into these new tunnels. Potential ‘routes’ have already been identified for these new tunnels - the first of which would run from Park Royal to Hackney Wick, while the second would run from Chiswick to Beckton - as well as a number of smaller tunnels and ‘flyunders’ across London.
Moving roads moved underground would "unlock land at the surface for thousands of new homes and open space", the mayor's office claims.
Two locations – the A13 in Barking and the A3 at Tolworth - would have the potential to release land for up to 6,000 homes combined, for example.
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", the mayor claims.
Johnson is also calling on the government to devolve the revenue from vehicle excise duty to London, so it can be invested directly into the capital's roads.
He said: “ Around eight of every 10 journeys in London are made using our roads – whether by car, taxi, motorbike, bus, cycle, foot, or freight – which is why it is vital that we think big.
"We must deliver long-term solutions that will not just make the most of the space we have for road users, but bring environmental and amenity improvements to local areas.
"Our major programme of capital investment in the city’s roads is transforming neighbourhoods across the city, making our roads safer, and cleaning up our air. But we need to go further. By pushing forward strategic initiatives we are outlining today, we will lay the foundation for the next wave of improvements to everyone’s experience of the road network across the city.”