Sorry, no sympathy for the RV drive here. The bridge, apparently, is clearly marked. What more can you really expect, the RV owner to know the clearance of his vehicle, no, no, no, that's just asking too much.
We have a similar looking railroad crossing in Charlotte, it's either on N. Tryon or N. Graham I think, just north of the downtown area. Anytime we get more than an 1" or so of rain, it turns into a moat. The only "cure" would be to close the road entirely.
BD