A San Francisco-based design firm called Gensler have won praise for a proposal to turn some of the abandoned parts of London's Underground tube line into one huge, interconnected cycle track for commuters.

The initial proposal is to utilise parts of the Jubilee and Piccadilly lines, while it would then conceivably expand to other abandoned parts of the city's tunnels, ultimately interconnecting the entire system and reducing traffic congestion above ground. 

The design won the Best Conceptual Project prize at the London Planning Awards, and would see kinetic paving from the friction of the bike's tires, creating electricity to illuminate the pavement.

It's a long way from reality, and would be expensive to construct, but it's still an intriguing concept and use of structure.

Via Mashable