Event Data Recorder (EDR) AKA "The Black Box"

Everyone has heard about the "black box" in an airplane. Modern vehicles have their own "black box", of sorts.  It's an electronic module designed to control the functioning of the supplemental restraint system in the vehicle.  Think of it as the brain of the air bag system. As a bonus, this device can record data in a crash, such as vehicle speed, braking, steering, seat belt use, acceleration, and other crash parameters.  This data can be imaged and analyzed as part of the investigation into your case.  Think of this "black box" as a witness.  A very good one.  The "black box" doesn't care who is at fault.  It simply records.