So, pretty much every car in this game has a radio, but they're all silent. My suggestion is to make them play music. And about copyright problems, doesn't have to be actual songs or music, could just simply be a few instruments, there's also copyright free music as well! Want to select a station? How about a car radio UI app? Hearing some rock music while ramming traffic out of your way in a ram plow truck is better than unpleasant crashing sounds.