Where I live a bike a lane is the space around me I can reach with my trusty 300mm Abus Granit x U-lock, which makes a very effective three-pound hammer.
But the nearby city of Cork is much more civilized. They have a bike lane, and, recognizing the realities, have built it to lead straight to the excellent Accident & Emergency department at Cork University Hospital. Here you can see this most thoughtful of cycle facilities. The road is the main drag to the dormitory communities of West Cork, the most trafficked road out of Cork (the photo was taken in the dead period between rush hours -- in the rush hour it's rather like NASCAR, shortening tempers bumping to pass). On my right as I take the photograph, is a bus shelter. Across the road is Cork University Hospital, where the young residents refer to cyclists as "organ donors". You can see the bicycle lane approaching, until it er-- just stops and er-- becomes the bus lane. Helpfully the bicycle lane continues in the middle of the road (at the extreme left of the photo, about halfway up), to turn right to A&E. Just in case any motorists haven't yet understood the message that they should run over the cyclists attempting to cross their space to "join" the two cycle lanes (those cyclists whom the buses swerving left to the stop haven't collected), there's a helpful white arrow on the road guiding the motorists into the lane the cyclists must cross...
(http://www.coolmainpress.com/miscimage/all_cycling_lanes_lead_to_accident_and_emergeny_photo_andre_jute.jpg)