Is a car safe during a lightning storm?

A hard-topped metal car is one of the safer places to be during a lightning storm, second only to a substantial building, but the popular explanation for why is wrong. It is not the rubber tires that protect you, that is a myth; a few inches of rubber is nothing to a bolt that just traveled miles through the sky and can jump enormous gaps. What actually protects you is the metal shell of the car, which acts as a Faraday cage: if lightning strikes the vehicle, the metal body conducts the electrical charge around the outside of the car and down into the ground, rather than through the interior where you are sitting. The electricity flows along the metal skin and dissipates, leaving the passengers inside the enclosed metal box largely shielded. This is the same principle that protects people in airplanes struck by lightning.

The important caveats: this protection requires an enclosed vehicle with a solid metal roof and metal sides. Convertibles, motorcycles, golf carts, cars with fiberglass or plastic bodies, and any open-topped or open-sided vehicle do not provide this shielding and are not safe. And even in a proper metal car, you should not touch metal parts connected to the frame during the storm (door handles, the steering column, radios, anything metal), and avoid contact with the metal exterior, because that is the path the current takes, keep your hands in your lap and do not lean on the doors. It is also wise to pull over safely and wait out the worst of it rather than driving through, since heavy rain and reduced visibility are their own hazard. So the honest answer: yes, a hard-topped metal car is a reasonably safe refuge from lightning, thanks to its conductive metal shell channeling the strike around you, not because of the tires, provided it is fully enclosed and you avoid touching the metal parts. If you can get into a real building instead, that is even better.