<TimTravellerVoice> if you want to visit the Fyllingsdaltunnelen, take the number two tram from downtown Bergen to Kristianborg, where you can rent a bike share for an hour. The trams are level boarding and the tunnel can also be used by walking or wheelchair.
@bleeptrack this one isn't a roundabout unfortunately, just an artificial sundial marking the halfway point. although I don't think the Faroe Island one allows cyclists, which makes Bergen's tunnel much cooler...