I know around me there are alot of roads just like yours and most people seem to think that since other homes are on the road that it isn't private even with signs. There are actually alot of people here that will post signs on roads and property that isn't private, but public and that throws off people even more. IMHO the only way to make sure nobody comes onto your land is a gate. I know its not something I would want to have to open and close constantly, but if all else fails its the only option that I can think of.