US Patent 7627414 Road map management system

A road map management system is provided as follows: drawing a past-direction distribution map (Image A) and a future-direction distribution map (Image B) using multiple vehicles' traveling position data collected via a wide area network during a past-direction data collection period and a future-direction data collection period, respectively; comparing the two distribution maps to extract a differential distribution; defining under a predetermined condition as a recently opened or closed road the differential distribution, which is absent from Image A and present in Image B, or present in Image A and absent from Image B, respectively; and reflecting the defined results on the existing road map data to update.