Abstract: In a school bus tracking system, each school bus is provided with a mobile station and an ID. The bus ID's and telephone numbers for the buses' mobile stations are stored in a tracking application/database. At a residence, a parent sends a message to the tracking application that includes the ID of a bus that services the residence, and a radius. The message may be sent using a short message service, i.e., a text message to a particular address utilized by the tracking application. Then, the tracking application causes the locations of the bus mobile station and the parent's mobile station to be periodically polled. When the bus mobile station comes within the radius, the tracking application issues a message to the parent mobile station alerting the parent that the bus is approaching. The system may be used to track other vehicles, objects (e.g., packages), and/or persons.