Almost one million miles of local and collector roads exist in the United States which do not possess sidewalks or an equivalent pedestrian facility.
For a number of reasons including low funding priority, low traffic volumes, etc, many of these roads will not receive sidewalks for decades, if ever.
Edge lane roads, also known as advisory bike lanes or advisory shoulders, provide an on-street, preferential space for vulnerable road users for just the cost of re-striping. An edge lane road is one which provides for two-way motor vehicle and non-motorized traffic using a center lane and "advisory" or edge lanes on either side. The center lane is dedicated to, and shared by, motorists traveling in both directions. Vulnerable road users (VRUs), such as cyclists or pedestrians have right-of-way in the edge lanes but motorists can use the edge lanes, after yielding to the VRUs there, to pass approaching vehicles. These edge lanes can be used to accommodate all types of alternative modes, e.g. personal mobility devices, skateboards, horse-drawn buggies (think Amish and Mennonite communities), etc.
More information is available at advisorybikelanes.com.