The presence and condition of shoulders may affect motorcyclist safety. A lack of shoulders offers a motorcyclist no place to take an evasive riding action if necessary. A stalled motorcyclist on a roadway without a shoulder or with only a narrow shoulder is especially vulnerable to moving traffic on the adjacent lane. A wide shoulder provides an errant motorcyclist recovery space before impacting a fixed roadside object. Paving currently unpaved shoulders so they can be used for these purposes is a recommended method of assisting in motorcycle recovery and avoidance maneuvers. Plans should ensure that paved shoulder edges are tapered to the unpaved area and do not present a dropoff.

Shoulder width and AADT are critical factors that influence motorcycle crash frequency. In rural environments, locations with narrow shoulders provide little recovery space for vehicles negotiating a horizontal curve. Rural roadways with shoulder widths of 6-ft or less will have approximately 52 percent greater likelihood of crashes occurring at horizontal curve locations.