I have a vision of a Bicycle Subway of the distant future where subway tunnels run underground throughout the city with exist at convenient locations. These subways will have mechanized ramps of the future which aid bicycles up to the surface level and down to subway levels as if one were cycling on level ground like cycling escalators. These subways would be lit all the time with future energy efficient lighting with security device like cameras for safety and crisscross under the city. They would be maintained naturally at a constant temperature of about 65-70 degrees and protected from the outside weather by air curtains at each surface exit.
Shopping areas would be scattered at intersecting tunnels throughout these bicycle subways and limited pedestrian traffic permitted. These subways would also intersect major mass transit hubs with bicycle racks for parking bikes and commuting to distant locations. Mass transit would consists of pneumatic ram trains that are run by compressed air that push these trains in tunnels like pneumatic tubes used for delivering receipts. Pressure ports would be located every few feet throughout the tunnels and pressure controlled but future super-computers so that various trains can stop and start individually or as a large group of trains. These ram trains will be designed to efficiently accommodate a certain number of bicycles that can be hung from the ceiling or located under the sitting area.
These Bicycle Subways may be more than one level deep and would supplement the surface bicycle streets and provide year round sheltered cycling conveniently throughout the city and beyond.
Perhaps a century from now many people might actually live underground in communities along these underground tunnels to allow for more population density. A century from now our spacious houses on spacious lots will be viewed like old Victorian Mansions are viewed by us today. The conveniences and technology of the future will compensate for the apparent lack of space. In reality we live in a very space environment compared to many in extremely large and crowded cities such as Tokyo, Hong Kong, New York City or even areas of San Francisco.