On of the best examples of such an expressway is located in Lyon, France (map under). The Le Tube runs in parallel with the 2 km Croix Rousse road tunnel and is a mixed traffic tunnel where regular road traffic is in one tube and pedestrians and bicycles are in a second tube (Le Tube). In addition busses have a separate lane in the pedestrian/bicycle tube. Le Tube is more or less a continuous art experience, with sound effects and projected images combining to create a fantasy realm of light.
Safety and security issues are quite important in these kind underground structures. Anxiety caused by fear for narrow passages, but also that the road user need to feel safe from crime, is essential. When such a passage becomes several km long, this is of course a crucial issue. It´s seems like the safety issues is quite well taken care of in the Le Tube in Lyon.
In an operation perspective a pedestrian/bicycle tunnel is quite easy to operate and maintain, because the contractors can at any given time inspect and do small work without disturbing the traffic flow. Pedestrian and bicycle tunnels are often closed during night to prevent the underground structure to be a resting place for homeless people. The closing period at night can therefore be used for more extensive maintenance work and rehabilitation.
To maintain a steady warm environment is difficult and the final tunnel system can be more complex when you have to make sure that the tunnel is an inviting environment for the users when it comes to temperature and draft. A tunnel system for pedestrians and bicycles may be more difficult to design for a cold climate.
In Bergen (Norway) they plan to build a 3 km long pedestrian/bicycle tunnel. If this concept is given priority from the politicians, the tunnel will go from Bergen city to one of the suburbs (Fyllingsdalen). The bicycle tube will be a parallel tube to the new light rail tunnel. Similar plans has been revealed for similar tunnels to other suburbs in Bergen.
From the city center area (right) to Fyllingsdalen (left).
Photo: Norwegian Public Roads Administration.