Systems and methods for providing the crew of an airplane or vehicle with a potential traffic-threat alert. When the alert is triggered is based on presumed flight-crew action and reaction times, ownship speed, and required distance to safely stop the ownship before intersection with traffic. An exemplary system located aboard an ownship includes a communication device that receives information from a ground traffic; a memory device that stores ownship information and predefined constants; and a processing device that determines a distance to the traffic when the traffic passes the ownship after the ownship stops at an estimated full-stop location, based on the received ownship information and the predefined constants, determines distance to the ground traffic vehicle, based on the determined point in time, and generates a potential collision alert if the determined distance is less than a predefined safe distance value. An output device outputs the generated potential collision alert.