The word monocoque is a French term for single shell or (of boats) single hull.[1] A true monocoque carries both tensile and compressive forces within the skin and can be recognised by the absence of a load carrying internal frame. By contrast, a semi-monocoque is a hybrid combining a tensile stressed skin and a compressive structure made up of longerons and ribs or frames.
Some tornadoes move faster than some cars (record speed for a tornado moving across land is 72.6 mph (116.8 km/h)), even when the road is clear and flat. Any of these situations can leave drivers stranded in the path of the tornado far from substantial shelter.
Even the smallest tornadoes have hurricane-force winds; some have wind speeds of up to 300 miles per hour. A car, van or truck can't offer much protection from those winds or from the debris hurled through the air by the twister. Your first reaction when you see a funnel cloud may be to drive to get away from it.