Methods and systems for increasing the precision of a map include receiving a plurality of messages over a network from a corresponding plurality of vehicles. The vehicles may be equipped with positioning devices such as a global positioning receiver. The positioning devices in the vehicles may be of a lower cost and therefore provide location precisions within approximately ten (10) meters. The locations of the plurality of vehicles may be used as control points in one or more interpolation algorithms to adjust the position of road information included in a map. Thus, higher precision maps may be generated through the use of relatively lower cost positioning devices in the vehicles.