They kind of do...it's called True Crime: New York City. Except without all the GTA IV features and LCPDFR features, but hey, you're still a police officer and you make almost any car into a police car.
That's very true but I never got into that game much. I never found the game realistic which I don't think it was suppose to be at all, but it wasn't too bad of a game. I still like this idea, but I think there is only so much you can do in a video game, especially a big importance is the AI on how they react to situations.