There is disclosed a system and method wherein precise geographical location information such as Global Positioning System coordinate data is utilized as a principal criterion for implementing other wireless transmitted instructions and communications advising vehicles, and others, of an approaching emergency vehicle, the proximity of a hazardous condition, or virtually any other situation which is relevant to the intended recipient because of their location. The system and method further can involve intervention and control of a vehicle, such as an aircraft or automobile, which comes into a predetermined location or area, or under other circumstances. The system and method use transmitting units and receiving units, both of which can receive geographical positioning information and which may sound or otherwise output an appropriate advisory, warning or other communication selected based on their positions, heading, and/or speed.