The real problem with this area, and what the NPS won’t fix, is the corkscrew bridge. It should never have been built this way. It should have been a smooth sweep from the top down onto a trail just past the entrance to the parking lot. This would have allowed all pedestrian, and bike traffic to avoid the parking lot all together. Instead they have to figure out how to make a very non-ideal area safer and easier. Not likely.
Do the smart thing: rebuild the bridge and forget stop gap fixes. As bike commuting continues to increase this will become even more critical and area to have working smoothly and safely.