The Kennedytunnel in Antwerp is two-level with a bike tunnel on top of the (very crowded) motorway, and it does smell of fumes in spite of the ventilation. The

The Kennedytunnel in Antwerp is two-level with a bike tunnel on top of the (very crowded) motorway, and it does smell of fumes in spite of the ventilation. The large detours of the bike path at both ends of the tunnel are also a bit annoying as they significantly increase the distance you have to cycle. The alternative with elevators like in the Sint Annatunnel isn't really better though, because there you just have to wait for a long time for the elevator. I much prefer bridges but where I've used bike bridges (like in Nantes) they were very low with little clearance above water. Even in Lille they're just a few meters, maybe ten meters at most, above water, so they're easy to climb without a large detour. I wouldn't take the Pont de Cheviré on a bike for example...