Twice recently I've encountered the belief that weathering a lightning storm in a car is a good idea because the rubber tyres insulate it from the ground. I disagree.

I accept that a car is well insulated, but we're talking about a potential difference that has already broken down the impedance in dozens or hundreds of metres of air to get to the car: we're assuming it can't go the last few inches between a car chassis and the road?

I think it's more to do with the fact that a car is a Faraday cage: an all-enclosing shell of conductor that channels electricity around what's inside. Lightning takes the path of least resistance to earth, and since the car has much less resistance it's not going to go through you (I think you could probably still get burnt by being too close to the car body when it does, but it's nothing compared to what you get by conducting it to ground yourself).

Common perception is that it's the tyres though. I stuck to my guns when one of my work colleagues said so, but the other time I was contradicted it was a character in CSI. Although granted it was in the same episode that a different character claimed that 'terminal velocity is 9.8 metres per second per second'...

So does anyone else have an opinion, or better, some knowledge?