Bike lanes don’t protect riders when they cross intersections. Protected intersections do. Buffer zones at intersections protect bicyclists. Turning vehicles make 90% turns at slower speeds, making it much easier for drivers to see riders. Two sets of traffic lights, one for cars, one for bicycles, allows bicyclists to either have the entire intersection for themselves for a short period or they get a headstart of a few seconds in which to make turns and cross.
The video, by urban planner Nick Falbo, explains how protected intersections work. http://www.treehugger.com/bikes/next-breakthrough-bike-friendly-world-protected-intersections-video.html
More at protectedintersection.com