OBD GPS Logger does exactly what it says on the tin. OBD GPS Logger logs OBDII and GPS data on Mac OS X. It can then take that logged data and write useful output formats. Your car has lots of interesting things it can tell you from its on-board computer while it's running. These are OBDII data - how fast you're going, how fast the engine's going, the air flow into the engine, the throttle position, etc. This tool logs into these OBDII data for you.