In some examples, a system to produce refined location information for multiple vehicles may aggregate GPS coordinates collected from each of multiple devices over a period of time, estimate a location for each of the multiple devices at intervals during the period of time, track the locations for each of the multiple devices over the period of time, and determine a current location, on a road, of the vehicle corresponding to each of the devices based on a detected trend of the tracked locations for each of the multiple devices over the period of time.