Abstract: A system and method for determining a route of travel and associated mileage of a vehicle is disclosed. The system records a vehicle's identification number, location, and odometer mileage transmitted via satellite to a fixed station. The location data is provided to a processor which determines an estimated route of travel by said vehicle using a routing program. The estimated route is comprised of a plurality of position segments, each position segment having a corresponding mileage and average expected speed. The route of travel may be checked for accuracy by comparing the estimated route mileage to the odometer mileage. If a significant difference is found, a diagnostic procedure is performed which attempts to correct the mismatch by evaluating alternate routes of travel. If the alternative route mileage agrees with the actual odometer miles within a predetermined threshold, the new route and associated mileage is used as the "true" route taken by the vehicle.