Mr Johnson revealed five locations where underground roads could be built – the A4 in Hammersmith, the A13 in Barking Riverside, the A3 in Tolworth, the A316 at Chalkers Corner and the A406 in New Southgate.
The Mayor is currently on a six-day visit to Boston in the US. He was invited on a tour of Boston’s “big dig” regeneration project, which saw major highways diverted underground.
Speaking to the BBC, he said: "It's the sort of thing we can do in Hammersmith where the A4 is a very old mouldering flyover, which we could take underground, releasing a huge amount of land that could be turned into a park, several parks, and other amenities, plus releasing a lot of land for housing.”
"You could use some of the proceeds from that housing to pay for it and you would probably also have to look at tolling as well."
Further information on five locations:
- A new mini-tunnel for the A13
- Decking of the A3 in Tolworth
- A small 'fly-under' on the A316 at Chalkers Corner in Richmond
- A 'fly-under' at the A4 in Hammersmith
- Decking or a mini-tunnel at the A406 in New Southgate.
According to the BBC, Transport for London will now work with local boroughs on the proposals and an analysis including funding options will be presented to the mayor in May.