I think there are plenty of roads on public lands already -- enough for my use, anyway. Providing an opportunity for more people to drive on more roads in no way improves my enjoyment of the outdoors.
Declaring an area off-limits to vehicles in no way locks it up. On-foot is the best way to travel if you want to experience what an area is like in its natural state. Not physically able to travel by foot? Well...I don't believe that everything needs to be made handicap accessible. I'm not in good enough shape to hike/climb to some places in the some wilderness areas, and that's fine with me -- it's enough to just know that they're there -- protected.
Well said!