A roadway that is open to both bicycle and motor vehicle travel - may be an existing roadway, street with wide curb/outside lanes, or road with paved shoulders. Shared roadways typically have no bikeway designation, but should be designed and constructed under the assumption that they will be used by bicyclists.  Lanes are typically 12 feet wide or less, allowing cars to safely pass bicyclists only by crossing the center line or moving into another traffic lane.