Traffic information providing system and car navigation system

• US 20050093720A1
• Filed: 09/02/2004
• Published: 05/05/2005
• Est. Priority Date: 10/16/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kumagai, Masatoshi, Endo, Yoshinori, Matsuo, Shigeru, Yamane, Kenichiro, Machii, Kimiyoshi, Yokota, Takayoshi, Fujiwara, Junsuke
• Granted Patent: US 7,355,528 B2
• Time in Patent Office: Days
• US Class Current: 340/995.13
• 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: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096838 where the user preferences are taken into account or the user selects one route out of a plurality
• CPC Class Codes: G08G 1/096883 where input information is obtained using a mobile device, e.g. a mobile phone, a PDA

Abstract

A traffic information providing system externally acquires traffic information including information relating to the travel time of a link, calculates a travel time for a non-provision link to which no travel time is provided through estimate/complement operation. The estimate/complement operation is carried out with use of travel times, emergencies, travel times of links in the vicinity of the non-provision link, and so on, obtained in the near past. The system stores and statistically processes the externally-acquired traffic information, and also estimates a travel time in the near future. When there is an abnormality in the acquired traffic information, the system deletes the abnormality, regards the information as a non-provision link, calculates a probability distribution of travel times of links, calculates a probability distribution of travel times of the entire route made up of a plurality of links, and also calculates a probability for a specific travel time range.

Claims

1. A traffic information providing system for creating traffic information to be used in a car navigation system, comprising:

traffic information acquiring means externally acquiring traffic information including information relating to a travel time of each of links making up a road on a map;

storage means for storing the traffic information acquired by the traffic information acquiring means;

statistical means statistically processing past traffic information stored by the storage means; and

complementing means calculating traffic information relating to a travel time for a non-provision link to which information about a travel time is not provided by the traffic information acquiring means, through estimate/complement operation on the basis of the statistical processing of the statistical means and traffic information about links in the vicinity of the non-provision link.

2. The traffic information providing system as set forth in claim 1, wherein the traffic information acquired by the traffic information acquiring means includes information about a date on which the traffic information is collected, the non-provision link is a link which includes at least a non-provision time for which no travel time is provided, and the complementing means has a function, when performing the estimate/complement operation over a travel time at the non-provision time of the non-provision link, of calculating, as the travel time for the non-provision time, an average value of time points in a predetermined time range after and before the non-provision time by weighting the travel times at time points for which travel times are provided in an order of departing from the non-provision time.

3. The traffic information providing system as set forth in claim 1, wherein the traffic information acquired by the traffic information acquiring means includes a congestion degree at each collection time point of the traffic information and information about a length of a section showing the congestion degree;

the complementing means has a complementing function of calculating a travel time for the non-provision link with use of the congestion degree of the non-provision link, the length of the section indicative of the congestion degree, and a travel speed corresponding to each predetermined congestion degree; and

the complementing function, when an unknown-congestion-degree section is-included in the non-provision link, has at least one of a function of treating the unknown-congestion-degree section as a normal congestion degree section, a function of treating the unknown-congestion-degree section as a section having the same congestion degree as a section having a known congestion degree in the non-provision link, and a function of treating the unknown-congestion-degree section as a section having the same congestion degree as the section having the known congestion degree having a length of each congestion degree obtained by multiplying a ratio of the known-congestion-degree section for each congestion degree by a length of the unknown-congestion-degree section.

4. The traffic information providing system as set forth in claim 1, wherein the complementing means has a function, with respect to ones of links in the vicinity of the non-provision link which are not oriented to a direction opposed to an advancing direction of the non-provision link, of calculating a travel time for the non-provision link by comparing the travel time of a link directly connected to the non-provision link or the travel time of a link away by a predetermined distance from the non-provision link with travel times for the other links and by weighting the travel times.

5. The traffic information providing system as set forth in claim 1, wherein the complementing means has a function, with respect to ones of links in the vicinity of the non-provision link which are on the same route as the non-provision link, of calculating a travel time for the non-provision link by comparing travel times of the links on the same route with travel times of the other non-same-route links and by weighting the travel times.

6. The traffic information providing system as set forth in claim 1, wherein the complementing means has a function of calculating a link travel time for the non-provision link by weighting the travel times of links in the vicinity of the non-provision link in an increasing order of the number of predetermined main intersections between the non-provision-link vicinity links and the non-provision link.

7. The traffic information providing system as set forth in claim 1, predicting means for predicting a travel time for a specific link after passage of a predetermined time point.

8. The traffic information providing system as set forth in claim 1, comprising abnormal value deciding means for deciding one of the traffic information acquired by the traffic information acquiring means which is abnormal, and means for removing the traffic information decided as abnormal by the abnormal value deciding means, wherein the abnormal value deciding means has at least one of a function of deciding traffic information having a congestion rate of a predetermined value or more in a constant period as abnormal, a function of deciding one of traffic information on a plurality of days in an identical time zone which has a deviation larger than the other traffic information as abnormal, and a function of deciding one of the traffic information which has a constant value as abnormal when the travel time and congestion information of links in a constant period are compared and when one varies in a normal range but the other has a constant value.

11. A car navigation system comprising:

means for acquiring traffic information created by the traffic information providing system set forth in claim 1;

and

means for displaying traffic information about a non-provision link and traffic information not associated with the non-provision link in different forms when displaying the acquired traffic information.

9. A traffic information providing system for creating traffic information to be used in a car navigation system, comprising:

traffic information acquiring means for externally acquiring traffic information including information about a travel time of each of links making up a road on a map;

storage means for storing the traffic information acquired by the traffic information acquiring means; and

travel time probability calculating means for calculating a probability distribution of travel times of the links with use of past traffic information stored by the storage means.

10. The traffic information providing system as set forth in claim 9, comprising:

route travel-time probability calculating means for calculating a probability distribution of travel times of a specific route making up a plurality of links with use of the probability distribution calculated by the link travel-time probability calculating means; and

means for calculating a probability for a specific travel time range with use of the probability distribution calculated by the route travel-time probability calculating means.

12. A car navigation system comprising:

means for acquiring information about the probability for the specific travel time range of the specific route created by the traffic information providing system set forth in claim 10 from the traffic information providing system; and

means for displaying information about a probability for the specific travel time range of the acquired specific route.

13. A car navigation system comprising:

means for acquiring information about a probability distribution of travel times of links created by the traffic information providing system set forth in claim 9;

route travel-time probability calculating means for calculating a probability distribution of travel times of a specific route making up a plurality of links with use of the probability distribution of the link travel times;

setting means for setting a travel time range or a travel time probability for the specific routes;

reliability calculating means, when the travel time range of the specific route is set by the setting means, for calculating a probability that the travel time of the specific route is in the travel time range set by the setting means with use of the probability distribution of travel times of the specific route and, when the travel time probability of the specific route is set by the setting means, and for calculating a travel time range in which the travel time of the specific time falls in the travel time probability set by the setting means with use of the probability distribution of travel times of the specific route; and

reliability display means for displaying a result calculated by the reliability calculating means.

14. The car navigation system as set forth in claim 13, comprising a changing means, when the result calculated by the reliability calculating means fails to satisfy predetermined conditions, for changing the travel time range or the travel time probability set by the setting means, and wherein the reliability calculating means has means for regarding the travel time range or the travel time probability changed by the changing means as having set by the setting means and for again performing the calculation.

15. The car navigation system as set forth in claim 13, comprising means, when displaying traffic information about a plurality of the specific routes, for displaying the traffic information in an increasing order of the route travel times or in a decreasing order of the probabilities for the travel time.