Traffic congestion degree determination device, traffic congestion degree notification device, and program

摘要

When an average vehicle speed corresponding to a congested road section exists and at the same time, speed limit data corresponding to the congested road section is contained in map data, a degree of traffic congestion is determined based on the difference between the average vehicle speed and the speed limit. When an average vehicle speed corresponding to a congested road section exists but speed limit data corresponding to the congested road section is not contained in map data, a degree of traffic congestion is determined based on the average vehicle speed. When there is not information indicating an average vehicle speed corresponding to a congested road section, a degree of traffic congestion indicated in externally received traffic information is directly taken as the result of determination of a degree of traffic congestion.