A system for determining whether a vehicle having an associated vehicle path is within an allowed approach of a location, comprising: navigation means, associated with the vehicle, for generating vehicle data at periodic intervals along the vehicle path, wherein the vehicle data includes vehicle position data; means for transmitting the vehicle data; means, associated with the location, for receiving the vehicle data; mapping means, associated with the location, for storing a plurality of positions corresponding to allowed approaches to the location and providing therefrom a map of allowed approaches; evaluation means for comparing the vehicle data to the map of allowed approaches to determine whether the vehicle path is within an allowed approach. view more

The system of claim 1 wherein the navigation means is adapted to use signals received from a Global Positioning System (GPS).

The system of claim 1 wherein the vehicle data comprises position, heading and velocity data corresponding to the vehicle.

The system of claim 1 wherein the vehicle data further includes vehicle heading and vehicle velocity data.

A traffic control preemption method which uses data received from a global positioning system (GPS) to determine whether a vehicle, having an associated vehicle path, is allowed to preempt traffic signals at an intersection, comprising the steps of: (a) receiving GPS signals; (b) processing the GPS signals on-board the vehicle so as to generate vehicle data; (c) transmitting the vehicle data; (d) providing a map of allowed approaches, wherein the map of allowed approaches comprises a plurality of preprogrammed allowed positions proximate to the intersection; (e) comparing the vehicle data with the map of allowed approaches; (f) determining, based on comparing step (e), whether the vehicle is within one of the allowed approaches; and (g) allowing the vehicle to preempt the traffic signals associated with the intersection if the vehicle is within one of the allowed approaches. view more

The traffic control preemption method of claim 16 wherein the step of transmitting vehicle data comprises the step of transmitting vehicle position, heading and velocity data.