Buffer Zone . BLs provide a tangible buffer for pedestrians, especially along roads with no sidewalk setback from the curb. BLs are also a buffer for drivers pulling out from driveways to enter the roadway. This is good for drivers, bad for bicyclists who may be obstructed or struck. WOLs are not a formalized buffer, but provide greater separation distance than a standard width lane.
BLs are politically difficult to remove once in place.
A WOL may be more easily converted to additional travel lanes. This should not be a problem in Chapel Hill however. It is argued that BLs in urban areas diminish the availability of on-street parking, which, from a cyclist's viewpoint, is not all that bad. However, once painted, BLs have ha habbit of staying in place. Parking narrows the available travel corridor, reducing driver overtaking space and causing some bicyclists to feel less comfortable.