Most old roadbeds are simply abandoned after they become impassible. S.O.P. is to move over a vehicle-width, and start a new path. When that wears out, do it again, and so forth. Near Santa Fe, there are places where the old Camino Real has thirty-five abandoned beds, side-by-side. Abandoned roads continue to cut. They must be treated or they will do vast damage over decades. See Installment #1 of this series for an example.
Pictured below is a valley bottom that contains three roadbeds, side-by-side. The bottom is recovering after the roads were ‘put to sleep’.
Below: This road has been ‘put to sleep’ with small dams. Note that the wheel ruts are now filled in and sprouting with grass and forbs.
Once the water slows, the scouring stops. The fine particles fill in and plants grow.
Below: A close shot of a dam, with forbs and grasses growing in the old roadbed.