1. A method comprising: receiving accelerometer data indicating a change in a motor vehicle velocity; processing the accelerometer data to determine acceleration amplitude versus time date; determining a preliminary crash detection decision indicating that the motor vehicle may have experienced a crash when the acceleration amplitude is greater than a predetermined accelerometer threshold; determining a time associated with the preliminary crash detection decision; receiving velocity data of the motor vehicle; processing the velocity data to determining amplitude of change in velocity versus time data at time data associated with the preliminary crash decision; and determining the motor vehicle has experienced a crash if the amplitude of change in velocity data is above at least one of a predefined velocity threshold or a percentage change velocity threshold when the value of the acceleration amplitude data was determined to be greater than the predefined accelerometer threshold.