How Does Your Car Protect You From Lightning?

While taking shelter in a permanent structure is always the best course of action during a thunderstorm, vehicles are generally regarded as a safe alternative.  Only tornadic winds have the strength to flip a typical vehicle and while cars may be dented, only exceptionally large hail will actually break through the windows.  Most importantly, vehicles are known to be a safe place to avoid being struck by lightning.  But how do vehicles protect us from lightning and do all vehicles protect us equally?

A common belief is that the rubber tires on cars insulate the vehicle from the ground, protecting the occupants should lightning strike.  While rubber is an electric insulator, the amount of voltage carried by a lightning bolt is far too great to be insulated by rubber.  It is not the tires of vehicles, but their metal frames which protect you from lightning.  When lightning strikes a vehicle, the metal frame of the car absorbs the electricity, conducts it around the occupants, and into the ground.  This means that as long as you're not touching anything metal inside your car at the moment of the strike, you will not be harmed.

Since it's the metal frame that protects you, it's important to note that only vehicles with a hard top are a safe refuge during a thunderstorm.  Even though convertibles have metal in them too, metal only conducts electricity; it does not attract it.  If you're inside a convertible, a lightning strike could miss the metal frame, easily burn through the soft top, and strike you inside.

Check out the BBC video below to see what happens when a lightning simulator is used on a car with a person inside.  The results are quite impressive!