Apparatus that is carried on a land vehicle, a marine vehicle or vessel, or an airborne vehicle or vessel for notifying others that a vehicle accident or other abnormal situation has occurred and for notifying others of the location of the vehicle at the time of the accident. The vehicle carries an distance measuring system (DMS) signal antenna and receiver/processor that receives DMS-type signals from one or more DMS signal broadcasters and determines the present position of the vehicle, plus an activatable transmitter. The vehicle also carries an abnormality sensing means that senses the occurrence of an accident or other abnormal situation involving the vehicle or a vehicle occupant. When an abnormal situation is sensed, the abnormality sensing means automatically activates the transmitter, which then communicates the fact that an abnormal situation has occurred and the location of the vehicle at the time the event occurred. Alternatively, the abnormality sensing means can activate the transmitter only after a vehicle operator has taken affirmative action indicating that the transmitter should be activated. Optionally, the transmitter can also communicate the time the event occurred. If the abnormal situation is (1) a vehicle accident, (2) inoperability of the vehicle, (3) inability of the vehicle operator or other vehicle occupant to continue (e.g., because of a rapid change in a present health condition of the occupant), the transmitter can also communicate information on (1) the severity of the accident, (2) the type or cause of vehicle inoperability, (3) the reason the operator or other occupant is unable to continue. Optionally, the system can also transmit, or hold for future analysis, the values of one or more vehicle operating parameters sensed at a sequence of times preceding occurrence of the abnormal situation. The DMS may be a Satellite Positioning System, such as the Global Positioning System (GPS) or the Global Orbiting Navigation System (GLONASS), or a ground-based radionavigation system, such as LORAN, Shoran, Decca or TACAN.