Patent ID: 7797101

Claim:
A road map display system for a vehicle, comprising: a position detector for detecting a current position of the vehicle; a map data storing unit for storing road map data; a display controller for displaying a road map, speed limit information of a road, and the current position of the vehicle in a display unit based on the stored road map data; a congestion information acquisition unit configured to acquire congestion information for a road from an outside information center; a display-switching target road selection unit configured to (i) define a road, of which speed limit information is displayed by the display controller, as a determination target road, (ii) determine whether congestion information for the determination target road is acquired, and (iii) define the determination target road, for which congestion information is acquired, as a display-switching target road; and a display form switching unit configured to switch a display form of speed limit information of the display-switching target road from a usual display form to a congestion display form for informing a user of a presence of the congestion information.