If that's really a concern, just build them with the clearance required of bridges over interstate highways, which is ~16 feet. Or provide a separate area for

If that's really a concern, just build them with the clearance required of bridges over interstate highways, which is ~16 feet. Or provide a separate area for huge vehicles - even if people transporting 200-ton mining haul trucks want to stop off at Wal-Mart en route, it's not like they'll expect to pull into standard bays.