If you wanted a radio you could do what nadeox1 said "Media Play In Background" Or just run a live radio feed off a website. - - - Updated - - - what I think would be cool if it was possible is if in a luxery car you could have a screen in the car that would play any video off your computer or something... always wanted that in a car game that you could free ride in... Like BeamNG
Most cars with movie players have a security system that doesn't allow to use the front monitor when the car is moving so it doesn't distract the driver.
Depends on which country it is. I know that in japan, you can get cars that have tv tuners built into the gps systems that allow you to watch tv while driving.