Motorists must also negotiate other natural barriers, such as mountains and river basins, that create roadway changes.
(Motorists; must negotiate; other natural barriers, such as mountains and river basins, that create roadway changes) (other natural barriers, such as mountains and river basins; create; roadway changes)
Motorists other natural barriers, such as mountains and river basins
must negotiate create
other natural barriers, such as mountains and river basins, that create roadway changes
roadway changes