The operator should shut down the equipment, close the doors, and sit with hands in lap, waiting out the storm. In no circumstances, during close-in lightning, should the operator attempt to step off the equipment to ground in an attempt to find another shelter. Lightning voltages will attempt to equalize themselves, and they may go through a person in order to do so. Smaller equipment without ROPS is not safe. Small riding mowers, golf cars, utility wagons are examples.
Rubber tires provide zero safety from lightning.
People should safely abandon this machinery and get into a safe shelter. Metal buses are good Faraday Cages. Pull over and wait out the storm. Reported damage to vehicles includes pitting, arcing, burning on both exterior and interior places. See the below photographs, courtesy of Mr. Brown, of his Jeep Cherokee which was struck by lightning.