The National Lightning Safety Institute gives us guidance about how lightning effects operators and their vehicles.
At lightning's higher frequencies, currents are carried mostly on the outside of conducting objects. For example, a thick copper wire or a hollow-wall metal pipe will carry most of the lightning on outer surfaces. This is termed the "skin effect." The same is valid when lightning strikes metal vehicles: the outer surface carries most of the electricity. The person inside this steel box is protected by a partial Faraday cage. However, it is not as simple as this and exceptions occur. Some general recommendations from the NLSI are as follows:
- Personal Safety Issues. A person inside a fully enclosed metal vehicle must not be touching metallic objects referenced to the outside of the vehicle. Door and window handles, radio dials, CB microphones, gearshifts, steering wheels, and other inside-to-outside metal objects should be left alone during close-in lightning events. It is safest to park the vehicle safely, turn off the engine and put one's hands in one's lap while waiting out the storm.
- Heavy Equipment. Heavy equipment that uses an enclosed rollover systems canopy (ROPS) is safe in electrical storms. The operator should shut down the equipment, close the doors, and sit with hands in lap, waiting out the storm. When lightning is close, the operator should never step off the equipment to the ground to find other shelter. Very dangerous step voltage and touch voltage situations are created when a "dual pathway to ground" is created. Lightning voltages will attempt to equalize themselves, and they may go through a person in order to do so. Smaller equipment without a ROPS is not safe. Small riding mowers, golf cars, and utility wagons are examples of unsafe vehicles. Rubber tires provide zero safety from lightning. People should safely abandon this machinery and get into a safe shelter.
- School Buses (or in the logging scenario – operator or labour transport). Metal buses are good Faraday cages. Make sure all windows are closed and the "hands on laps" rule is observed. Pull over and wait out the storm.
- Damage. Damage to vehicles includes pitting, arcing, and burning on both exterior and interior places. Cases have been reported of total destruction of vehicle wiring, and associated electrical and electronic systems. Cases from police departments report bad burns to the hands and mouth where officers were using radio microphones when their vehicles were struck. Cases describe total blow-out of all four tires in passenger cars. A video in the NLSI library shows a station wagon being struck by lightning in a heavy rain storm, with no damage whatsoever occurring.
For further information, see http://lightningsafety.com/nlsi_pls/vehicle_strike.html