A crash detection system with a mobile communications device configured for periodically interrogating (a) a motion signal to determine whether a change in motion (acceleration or angular rotation) exceeds a predetermined motion threshold and (b) a sound signal to determine whether a sequence of sensed sound signals within a predetermined period matches crash sound indicators of (i) glass breakage and (ii) metal folding, displaying selectable options upon detection of a crash incident, and upon a failure to select within a predetermined period, communicating an identifier and crash incident information dispatch center for dispatching a response servicer.