Having been a passanger once on a five hour trip with techno blasting at high volume for at least three of those five hours, it's dependable. If it's a short trip, play whatever you want, but if it's a long one, be considerate.
Yeah, I'd agree with this. Any trip longer than 20 or so minutes, then you should be considerate. (at a time, so if it's 20 minutes one way, spend a few hours, and 20 minutes back, play whatever you want the entire time)