There are other ways to mitigate the IED threat. Probably the best one is the one Schmedlap posted. Another is to decrease the size of A.O.s so that mounted patrols are not so necessary, but this is not always feasible and requires a larger amount of troops. The other is to stay off the roads by conducting dismounted patrols or, conducting old school mounted patrols via horse/donkey/camel (the original All Terrain Vehicle). But the other problem is re-supply. Small-scale re-supply in the future should be conducted with some kind of supply drop-ship UAV (one of the few times you'll hear me advocate a technological solution) but for large scale logistics I think the loggies are still going to be provisional route clearance for a long time.