I have a telescoping painters handle and meassured the exact height of the RV empty and air bags to max and tires to max, les than a 1/4 fuel tank no water and nearly empty propane tank, this is the max height granted it will not be so when loaded but that height is the minimum that I look for in gasoline station canopies, under passes, bridges and tree lined streets and if in doubt I will stop some distance from the canopy, underpass, bridge and use the painters handle to measure the actual height, I have the handle marked so that I only need to extend it and I can also measure the exact height by extending the handle to the lowest point and then using the tape to get a reading, only had to turn around once in Tucson under a railroad track, vandals had stolen the signs the LEO was gladd I did not go under and helped me turn arroundq.
Most people seem to never look up and only focus on the road and completely forget the height of the vehicle, this includes camp grounds where tree branches hang down, seen a lot of roofs and sides punctured from inatentive drivers backing into them, I always get out and walk the spot looking for obstructions above and also for depressions that might tilt the unit into a tree, specially in tree abundant first time visit for us, this is specially when arriving at night.
navegator