What is the basis for recommending a 4-ft-wide walkable shoulder in rural areas?
The 4 foot width of walkway or walkable shoulder is a suggested “absolute minimum” distance away from the travel lane that is needed to provide at least some level of separation between motorists with pedestrians who will be walking along the road. Having little or no “walkable” area along the side of the road is likely to result in pedestrians walking on the pavement edgeline or in the travel lane, which can be deadly to pedestrians, particularly at night or other times when visibility is low (fog, dawn or dusk, rainy conditions, etc.). Obviously, providing as much separation as feasible can further enhance pedestrian safety even beyond a 4-foot walkable shoulder. Certainly having an 8-or 10-foot shoulder is much preferred and will further reduce the likelihood of a pedestrian being struck by an errant vehicle.
