I drive the most likely route every day and it has been searched and searched again, both by Police and Sulsar. In the main it is just roadside verges with a few hedges. IMO he would be obvious if hit by a car, and that's without the searching taking place.I am not sure where the roadside searches took place, but would assume it was at least along the likeliest route he would have walked home. It's probably 50% hedgerow and 50% open fields.
On top of everything leading up to it I doubt that he got hit by a car and is lying in a ditch or hidden somewhere and hasn't been found yet.