Road map display system for vehicle

• US 20080040022A1
• Filed: 06/28/2007
• Published: 02/14/2008
• Est. Priority Date: 08/11/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tanaka, Hiroyuki
• Granted Patent: US 7,797,101 B2
• Time in Patent Office: Days
• US Class Current: 701/117
• CPC Class Codes: G01C 21/3694 Output thereof on a road map
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096758 where no selection takes place on the transmitted or the received information
• CPC Class Codes: G08G 1/096775 where the origin of the information is a central station

Abstract

A road assigned with speed limit information displayed in a display unit is extracted as a determination target road. Whether congestion information for the determination target road is acquired is determined. The determination target road, for which congestion information is acquired, is extracted as a display-switching target road. A display form of speed limit information of the display-switching target road is switched from a usual display form to a congestion display form to thereby inform a user of a presence of the congestion information.

Claims

1. 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.

2. The road map display system of claim 1, wherein:

the display-switching target road selection unit is configured to define, as a determination target road, a connected road in addition to the road, of which speed limit information is displayed by the display controller, the connected road being within a predetermined distance from the current position of the vehicle and connected with the road, of which speed limit information is displayed by the display controller; and

the display-switching target road selection unit is configured to further determine whether congestion information of the connected road is acquired.

3. The road map display system of claim 2, wherein

the predetermined distance from the current position of the vehicle used for defining a connected road is set as being larger as a road level of the connected road increases.

4. The road map display system of claim 1, wherein

the display-switching target road selection unit is configured to define, as a determination target road, a road, which has a difference from a travel road on which the vehicle travels, the difference being less than a predetermined value in at least one of a speed limit, a road width, and a road level.

5. The road map display system of claim 1, wherein

the display-switching target road selection unit is configured to define, as a determination target road, a road, of which speed limit information is displayed by the display controller and which has a difference from a travel road that the vehicle travels on, the difference being less than a predetermined value in an orientation.

6. The road map display system of claim 1, wherein

the display-switching target road selection unit is configured to define, as a determination target road, a second road in addition to a first road, of which speed limit information is displayed by the display controller and which has a difference from a travel road that the vehicle travels on, the difference being less than a predetermined value in an orientation,

the second road being connected with the first road and the travel road.

7. A method for superimposing speed limit information on a road map, the method comprising the steps of:

detecting a current position of a vehicle;

displaying a road map, speed limit information of a road, and the current position of the vehicle in a display unit based on road map data;

acquiring congestion information for a road from an outside information center;

defining a road, of which speed limit information is displayed in the display unit, as a determination target road;

determining whether congestion information for the determination target road is acquired;

defining the determination target road, for which congestion information is acquired, as a display-switching target road; and

switching 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.