Propane..unlawful to have fridge on...is incorrect...

Many commercial vehicles (think catering trucks and frozen food delivery trucks) operate with propane. Years ago, in the 70', with the rationed gas, I had a propane operated car. Going over federally controlled bridges, and through tunnels there is signage prohibiting propane (RV tanks are excepted). When they had inspections over Boulder Dam, RV propane was excepted. I think the response to the article originally posted misinterprets a Canadian regulation.