How to avoid an unpleasant shared use path

A couple of days ago I asked for a route from Selborne to the Devil's Punchbowl in Hampshire, part of a bigger loop. I can understand why the routing engine would send me along a shared use path, as it's slightly shorter and seems like a good traffic free option. Unfortunately it's a narrow pavement next to a dual carriageway of the A3 with traffic doing 70 mph a few inches away, with no barrier in place. Streetview link. Not the worst thing in the world as it was only a mile.

Again, I totally understand why this happened and it's like a reasonable choice, given the data available. I know the A3 fairly well, but I couldn't remember which sections of the path were behind barriers. In this case the back roads seem like the preferred option, and only add about 0.2 miles. Is there any way to mark it up as unprotected or intimidating in OSM so that it doesn't get chosen?