English architect Norman Foster revealed a huge futuristic project called "SkyCycle", in which cyclists could traverse London on elevated roads.
This project has as goal to build above UK's capital several roads which would connect with other roads, and build road exits to main places and streets in London. The network, which would have 221 km (136 miles) of roads and 200 entrances, could welcome 6 million people, each road would be able to accomodate 12,000 cyclists per hour, and cyclists won't encounter cars or pedestrians on these routes, so they will go faster from a place to and other in London.
The most interesting is its cost : £ 220 million (about $ 362 million). And thanks to rail infrastructure already present, this price is not too high for Network Rail, responsible for transport in London, so the project could be feasible. If it is the network construction could last about twenty years.
By the way, by seeing the picture, we could think that Foster has been inspired by the blue roads of Neo Seoul in 'Cloud Atlas' movie. "SkyCycle" project could be a first step before elevated highways for cars, motorcycles, trucks, and high-speed trains. But here, we have to wait a few decades to have all that in our cities.
Sources : The Verge and Huffington Post (french)