The short answer to that is who would be driving the car?...
Pretty sure there's legal implications of driving and recording a model at the same time
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Alternatively, could fake the car moving or something - probably wouldnt be that great.
The only other alternative is where another model or person is present to drive the car, this has happened in a few movies, in particular the 'earlier' movies but nowadays it tends to just be the model by herself for the shoot so it's almost impossible to do car movies where the model is the passenger.
Is this what you meant? Dave can probably give you a better explanation though.