Flying through the windshield. (Grand Theft Auto 4)

Can't find which file is responsible for the number of NPS, sparadise in transport, as well as their departure through the windshield. I noticed an interesting peculiarity that if to RAM the cops with the available stars, then they sit in the cabin like a glove, and if you hold the ramming maneuver is not being wanted, that peace officers go through the windshield like regular bots. It would be interesting to know where it is written.