Portion of the street designated by striping, signing, or pavement markings for preferential or exclusive use by bicyclists.  Bike lanes are established with appropriate pavement markings and signing to delineate the right of way assigned to bicyclists and motorists, and to provide more predictable movements by each.  Bike lanes are usually paired one-way facilities located on both sides of streets with moderate to heavy traffic volumes.  Steeply sloped streets can have bike lanes on one side for climbing, while it may not be necessary to stripe lanes on the downhill side because bicycle speeds approach motor vehicles on these sections. The minimum width of a bike lane is 4 feet in most areas, or 5 feet when adjacent to on-street parking or if measured from the curb face.  Bicycle lane design at intersections must be treated carefully to minimize conflicts between bicycle and auto movements.