I don't have any links or references, but for a VPS the most common method is a V-formation, usually with five members. Search commander is in the middle, usually on the road/path and then two searchers on each side. The tips of the V will be furthest out from the culvert and the first to get eyes on, the middle of the V will be close, if not next to the culvert and if something is seen, they can get a closer look and halt the commander and the vehicles following before something happens. Lead vehicle should be close enough to provide ECM/cover.
A box search can also be done afterwards, but I don't recall performing that. Usually once the lead vehicle passed the culvert, mount up and keep moving.