The carrec.img file stores a set of R3 files (files with an extension .rrr). These files contain path information used by the mission script for Grand Theft Auto: San Andreas and Grand Theft Auto IV. The paths are predefined and look unnatural during gameplay because the movement of the vehicle is very rigid. The paths ignore many stuff in the game including gravity and obstacles. Original San Andreas installation has 426 R3 paths. Maximum number of these paths is 475. GTA IV increases this limit. By default there are 1813 R3 paths. The limit appears to be located somewhere beyond 3000.