If I'd stopped roadside & found a deer that had signs of being downed by a hunter, I would call the local DEC officers and check with the nearest property owner for a 'missing' deer.. The DEC can make the call on what to do to prevent waste of the animal, and they also should be called if a shot animal goes into private land and the owners refuses permission to recover the animal. They can also tag it so you can legally take it without using your own tag. If they said we've done everything possible, I'd take it also, rather than let it go to waste.