Fellow RVers, my name is Mac McCoy aka Macthefireguy. I was asked to commit on this link about driving with propane on or off. I worked for many years as the training coordinator for the Oregon State Fire Marshall's office. I am also a full time RVer and teach fire safety classes at RV Rallies.
Some states require you to turn your propane off when entering tunels or some bridges. The newer propane appliances are designed to have automatic igniter's and not pilot lites. However, due to the vibration of our RV's, branch lines coming from the main line have been known to come loose or rupture because they rub against RV parts. Your safer if you shut off the propane at the tank. Some MH's are equipped with a toggle switch inside the unit to shut off the propane. How do you know the switch works unless you test it. Do you know how? The design of some propane compartments in 5ers lend itself to rupture the line.
Safety is not usually high on most RVer's list of things to do. Safety of you and your family should be the first thing on your list. This is only one of many questions we should all have about our safety while RVing. At this time according to US fire officials, we burn around 21,000 RVs a year with 6,800 total losses. The majority are Diesel MH's that have engine fires. 12v is tied for second with refridgator fires. As you know the 2 major brands of fridge manufactures have as of this date recalled 4 million units because they catch fire. That might help you to decide to shut off your propane.
Thanks for the opportunity to talk with you all, Mac