There is a sign on the Washington DC Crescent Capital Trail where I get on it in the morning that also says "closed at dusk." I do not know anywhere else there is such a sign. It is senseless, would totally rule out commuting in the colder months, and is universally ignored! I often ask myself who comes up with such brilliant ideas and rules - there is a plethora of them pouring out of the bureaucrats - but to keep my sanity I convince myself that they are simply a mistake, a typo perhaps, they forgot the word "never" in front of the sentence...