Using location data to determine traffic information

• US 6,594,576 B2
• Filed: 07/03/2001
• Issued: 07/15/2003
• Est. Priority Date: 07/03/2001
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: At Road Incorporated
• Inventors: Fay, James D., Yang, Xinnong, Fan, Rodric C.
• Primary Examiner(s): Zanelli, Michael J.
• Assistant Examiner(s): Gibson, Eric M
• Application Number:
  US09/898,682
• Publication Number:
  US 20030009277A1
• Time in Patent Office: 742 Days
• Field of Search: 701/117, 701/118, 701/119, 701/201, 701/202, 701/207, 701/208, 701/209, 701/211, 342/357.13, 340/990, 340/995
• 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 1/096811 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 1/096838 where the user preferences are taken into account or the user selects one route out of a plurality
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data
• CPC Class Codes: G08G 1/096872 where instructions are given per voice
• CPC Class Codes: G08G 1/096888 where input information is obtained using learning systems, e.g. history databases

Abstract

A system and a method for determining and disseminating current traffic information is presented. A traffic data compilation computer linked to a data network collects location data from mobile units, each of which is associated with an identification number. The computer compiles the location data, calculates the velocity of each mobile unit, compares the velocity of each mobile unit against speed limit data stored in a memory, and stores the difference. The traffic data compilation computer determines the traffic condition based on the difference between the velocity of each mobile unit and the speed limit. In addition, traffic data compilation computer may determine the fastest route between point A and point B under the current traffic conditions. Traffic data compilation computer determines the possible routes between point A and point B, retrieves the velocity data from a database, and derives the estimated travel time for each of the possible routes.

Claims

1. A method of determining current traffic conditions, said method comprising:

receiving a location of a mobile unit over a data network;

computing an actual velocity of said mobile unit using said location; and

calculating a parameter using said actual velocity and location, said parameter indicating traffic conditions surrounding said mobile unit, wherein said calculating comprises;

receiving a geographic specification from a user;

retrieving speed limit of a road segment located within the boundaries of said geographic specification;

calculating the difference between said speed limit and said actual velocity; and

selecting a traffic level indicator representative of said difference.

2. The method of claim 1, wherein said location is derived with at least one of:

Global Positioning System;

Time Difference of Arrival;

Angle of Arrival; and

ray tracing method.

3. The method of claim 1, wherein said data network comprises a wireless communication network.

4. The method of claim 1, wherein said data network comprises:

a wireless communication network; and

the Internet.

5. The method of claim 1, wherein said receiving occurs at a predetermined time interval.

6. The method of claim 1, wherein said calculating comprises accessing road data from a database.

7. The method of claim 1, wherein said calculating comprises:

accessing the speed limit of said location; and

calculating the difference between said actual velocity and said speed limit.

8. The method of claim 1, further comprising transmitting to a mobile unit an image representative of said geographic specification, said image superimposed with said traffic level indicator.

9. The method of claim 8, wherein said traffic level indicator comprises an accident indicator marking an accident site.

10. The method of claim 8, wherein said traffic level indicator represents a speed range at which said mobile unit is traveling.

11. The method of claim 8, wherein said geographic specification comprises at least one of:

a route;

a radius; and

a geographic area having objectively definable boundaries.

12. The method of claim 8, further comprising storing said geographic specification in a database for repeat use.

13. The method of claim 1, further comprising:

calculating an accuracy indicator based on the number of locations received, said accuracy indicator indicating a possible degree of error; and

transmitting said accuracy indicator to a user interface device over said data network.

14. The method of claim 13, wherein said accuracy indicator comprises a spread between a maximum velocity and a minimum velocity in a road segment.

15. The method of claim 13, wherein said accuracy indicator comprises standard deviation of said maximum and minimum velocities of a road segment.

16. The method of claim 13, wherein said data network comprises the Internet.

17. The method of claim 13, wherein said user interface device comprises a wireless device.

18. The method of claim 1, further comprising transmitting an alert signal to said mobile unit if said parameter reaches a preselected value.

19. A device for determining current traffic condition, said device comprising:

a processing unit;

a database coupled to said processing unit, said database storing results of calculation performed by said processing unit; and

a memory for storing maps, traffic level indicators, and road data coupled to said processing unit, each of said traffic level indicators being calculated based on a difference between a speed limit at a road segment, obtained from said road data, and an average velocity of vehicles at said road segment.

20. The device of claim 19, wherein said processing unit is coupled to a data network transmitting data to and receiving data from a plurality of mobile units.

21. The device of claim 20, wherein said database comprises a table indexed by a mobile unit identification number, said table containing velocities of each of said plurality of mobile units.

22. The device of claim 19, wherein said database comprises a table indexed by location, said table containing current average travel speed for a location.

23. The device of claim 19, further comprising a predictive database coupled to said processing unit, said predictive database storing traffic pattern based on a statistical analysis of past traffic cycles.

24. The device of claim 19, further comprising a historical database storing traffic patterns of a preselected area for a predetermined time frame in the past.

25. The device of claim 19, further comprising a marketplace traffic database coupled to said processing unit, said marketplace traffic database storing traffic information obtained from a user or a third party.

26. The device of claim 19, wherein said road data comprises at least one of:

speed limit for a road segment;

distance of a road segment;

location of gas stations;

location of toll booths;

an indication of whether said road segment is a one-way street;

an indication of whether there is a carpool lane on said road segment;

location of traffic lights and Stop signs; and

number of lanes on said road segment.

27. A method of estimating a travel time between a first geographic location and a second geographic location, said method comprising:

determining a route between said first and second geographic locations;

receiving locations of a plurality of mobile units along said route over a data network;

computing an average velocity of said plurality of mobile units on said route;

providing a traffic level indicator for said route based on said average velocity and a speed limit along said route; and

deriving said travel time using the distances of said route, and said traffic level indicator.

28. The method of claim 27, wherein said determining comprises using past traffic pattern stored in a database.

29. The method of claim 28, further comprising:

calculating a reliability of said travel time;

selecting a reliability indicator representative of the result of said calculating; and

incorporating said reliability indicator into said travel time.

30. The method of claim 27, further comprising creating a warning package if said average velocity is based on fewer than a minimum number of data points.

31. The method of claim 27, further comprising creating a warning package if said average velocity is based on a location data received more than a predetermined value of time.

32. A system for providing current traffic conditions, said system comprising:

a plurality of mobile units each adapted to provide a current location;

a wireless communication network accessible by said mobile units to report the current locations;

a data network linked to said wireless communication network; and

a processing unit linked to said data network to receive said current locations, said processing unit being adapted to compute a traffic level indicator based on an average velocity derived from said current locations of said mobile units.

33. The system of claim 32, wherein said mobile unit comprises:

a GPS code receiver;

a location data calculator coupled to said GPS code receiver;

a transmitter coupled to said location data calculator and to a data network; and

a port coupled to said location data calculator and to a user interface device.

34. The system of claim 33, wherein said user interface device comprises at least one of:

a display unit;

a Personal Digital Assistant; and

a telephone.

35. The system of claim 32, wherein said wireless communication network is selected from a group consisting of CDPD, GMS, iDEN, AMPS and CDMA.