Sharraxaadda

Many people over the years have gotten their vehicles stuck in this ditch. It is on the gravel side of Bad @#$% coffee parking lot. It is city property as our lot is mostly city easement. Is there anything we can do to keep people from driving into this ditch? Sometimes people are simply turning around and don't see it. We have put temporary orange cones which help but are not permanent. And since this is city property we can't do anything permanent