Road information provision server, road information provision system, road information provision method, route search server, route search system, and route search method

• US 7,418,338 B2
• Filed: 12/18/2003
• Issued: 08/26/2008
• Est. Priority Date: 12/24/2002
• Status: Active Grant

• Current Assignee: Navitime Japan Co. Ltd.
• Original Assignee: Navitime Japan Co. Ltd.
• Inventors: Suzuki, Yusuke, Kikuchi, Shin, Ohnishi, Keisuke
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US10/529,145
• Publication Number:
  US 20060031566A1
• Time in Patent Office: 1,713 Days
• Field of Search: 702/00, 70117-119, 70213-215, 342/357.06, 342/357.12, 340/988, 701117-119, 701/200, 701213-215, 701/209
• US Class Current: 701/117
• CPC Class Codes: G01C 21/3492 employing speed data or traffic data, e.g. real-time or historical traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968
• CPC Class Codes: G01C 21/3691 Retrieval, searching and output of information related to real-time traffic, weather, or environmental conditions arrangements for giving variable traffic instructions G08G1/09
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096741 where the source of the transmitted information selects which information to transmit to each vehicle
• CPC Class Codes: G08G 1/096775 where the origin of the information is a central station
• CPC Class Codes: G08G 1/096811 where the route is computed offboard
• CPC Class Codes: G08G 1/096816 where the complete route is transmitted to the vehicle at once
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data
• CPC Class Codes: G08G 1/096866 where the complete route is shown to the driver
• CPC Class Codes: G08G 1/096883 where input information is obtained using a mobile device, e.g. a mobile phone, a PDA

Abstract

A road information provision system or route search system has a terminal device such as a car navigation device 20a, portable telephone 20b, or PC 20c which specifies routes and issues requests for road information; a VICS center 40 which provides congestion information; a road information provision/route search server 10 which, in response to requests from terminal devices 20a to 20c, generates road information based on congestion information from the VICS center 40, and provides the road information to the terminal devices 20a to 20c; a dedicated circuit network 50 which connects the road information provision server 10 and VICS center 40 by dedicated circuits; a network 30 which connects the terminal devices 20a to 20c and road information provision/route search server 10 to enable communication; and a GPS 60 which provides position information. The system can determine shortest-route information of distance or time and congestion information.

Claims

1. A route search server for performing road route searches, comprising:

basic road network storage means for storing road network information;

congestion information storage means for storing congestion information;

congestion information processing means for generating congested road network descriptions with prescribed timing based on said road network information stored in said basic road network storage means and on congestion information stored in said congestion information storage means;

historical congested road network description storage means for storing the latest congested road network description among said congested road network descriptions generated by said congestion information processing means;

historical congested road network description storage means for storing past congested road network descriptions among said congested road network descriptions generated by said congestion information processing means; and

,

information provision processing means for generating route information by searching road routes from said congested road network descriptions stored by said congested road network description storage means or by said historical congested road network description storage means and from said road network information stored by said basic road network storage means based on route specification information, and providing the route information,

wherein said route information includes time information indicating the time of generation of the route information, and, when said time information is included by said route specification information, said information provision processing means selects said congested road network description at the time indicated by said time information from said congested road network description storage means or from said historical congested road network description storage means, and performs a road route search from the selected congested road network description and from said road network information stored in said basic road network storage means.

2. The route search server according to claim 1, wherein said information provision processing means generates said route information using map information and text information.

3. The route search server according to claim 1, wherein said information provision processing means generates, as route information, the shortest route, in terms of either distance or time, from said congested road network description, based on said route specification information.

4. The route search server according to claim 1, wherein, when congestion information stored in said congestion information storage means is indicated by travel times t(i) for unit routes (i), said congestion information processing means uses average velocities v for each route type to calculate the congestion distances L(i) for each unit route (i) comprised by a congested road network description according to the equation

L(i)=v·

t(i)

and generates a congested road network description.

5. The route search server according to claim 1, wherein said congestion information processing means calculates congestion distances L(i) for each unit route (i) comprised by a congested road network description, based on the basic distances L0(i) of each unit route (i) of said road network information stored in said basic road network storage means and on the distances x and/or y of congestion and/or slowdown in each of said unit routes (i) comprised by said congestion information stored in said congestion information storage means, according to the equation

L(i)=(L0(i)−

x−

y)+α

x+β

y

where α

is a weighting factor (>

1) for congestion, and β

is a weighting factor (>

1) for traffic slowdowns, and generates a congested road network description.

6. A route search system, comprising:

a terminal device for specifying routes and requests road information;

a congestion information center for providing congestion information; and

,

a route search server for generating route information based on said congestion information from said congestion information center in response to a request from said terminal device and providing said route information to said terminal device, wherein said route search server is the route search server according to claim 1.

7. The route search system according to claim 6, wherein said terminal device obtains current position information from a GPS (Global Positioning System), and uses said current position as the starting position of a specified route.

8. A route search method of providing route information for a specified route, the method comprising the steps of:

(A) storing the basic distance L0(i) and type of each unit route (i), as well as the average velocity v for each route type, as road network information;

(B) obtaining and storing congestion information with prescribed timing;

(C) generating the latest congested road network description based on said road network information and on said congestion information, with the same or different timing as step (B);

(D) storing currently stored congested road network descriptions as historical congested road network descriptions, and updating by said latest congested road network description;

(E) calculating the course and time based on said latest congested road network description or said historical congested road network descriptions in response to a route search request, and calculating the distance of said course based on said calculated course and on said road network information, and generating the course, distance and time as route information; and

,

(F) adding time information indicating the time at which the route information was generated to said generated route information, and providing said route information.

9. The route search method according to claim 8, wherein, in said step (E), when time information is comprised by a route search request, the congested road network description at the time indicated by said time information is selected from said latest congested road network descriptions or from said historical congested road network descriptions, and route searching is performed.

10. The route search method according to claim 8, wherein, in said step (B), travel times t(i) for each unit route (i) are obtained and stored as congestion information, and that in said step (C), average velocities for each route type are used to calculate congestion distances L(i) for each unit route (i) comprised by the congested road network description according to the equation

L(i)=v·

t(i)

and the congested road network description is generated.

11. The route search method according to claim 8, wherein, in said step (B), distances x and/or y of congestion and/or slowdown for each unit route (i) are obtained and stored as congestion information, and that in said step (C), congestion distances L(i) are calculated for each unit route (i), based on basic distances L0(i) for each unit route (i) of said road network information and on distances x and/or y of congestion and/or slowdown for said unit routes (i) comprised by said congestion information, according to the equation

L(i)=(L0(i)−

x−

y)+α

x+β

y

where α

is a weighting factor (>

1) for congestion, and β

is a weighting factor (>

1) for traffic slowdowns, and a congested road network description is generated.