Methods and systems for estimating road traffic

• US 9,786,161 B2
• Filed: 04/01/2013
• Issued: 10/10/2017
• Est. Priority Date: 04/01/2013
• Status: Expired due to Fees

• Current Assignee: Qatar University Qstp-B
• Original Assignee: Qatar University Qstp-B
• Inventors: Filali, Fethi
• Primary Examiner(s): Khatib, Rami
• Application Number:
  US14/395,758
• Publication Number:
  US 20160012722A1
• Time in Patent Office: 1,653 Days
• Field of Search: None
• CPC Class Codes: G08G 1/0112 from the vehicle, e.g. floating car data [FCD]
• CPC Class Codes: G08G 1/0116 from roadside infrastructure, e.g. beacons
• CPC Class Codes: G08G 1/0125 Traffic data processing
• CPC Class Codes: G08G 1/0145 for active traffic flow control
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence
• CPC Class Codes: G08G 1/052 with provision for determining speed or overspeed speed measuring in general G01P
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04W 4/44 for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H]

Abstract

Disclosed are systems and methods for estimating road traffic in a road segment at a given time. The system comprising: a central server; and at least one of one or more mobile communication units installed in a vehicle passing the road segment at the given time, wherein each of the mobile communication unit is capable of sending a plurality of mobile spot values to the central server, and one or more fixed communication units installed for detecting wireless enabled objects in vehicles passing the road segment at the given time, wherein each of the fixed communication unit is capable of sending a plurality of detected spot values to the central server. The central server is capable of processing the at least one of the plurality of mobile spot values and the plurality of detected spot values to estimate road traffic in the road segment at the given time.

Claims

1. A system for estimating road traffic in at least a road segment at a given time, comprising:

one or more mobile communication units installed in a vehicle passing the road segment at the given time, wherein each of the mobile communication unit sends a plurality of mobile spot values to a central server;

one or more fixed communication units installed for detecting wireless enabled objects in vehicles passing the road segment at the given time, wherein each of the fixed communication unit sends a plurality of detected spot values to the central server;

a spot time window of a traffic estimation module for extracting from a database of the central server the plurality of mobile spot values and the plurality of detected spot values mapped to each road segment for computing an average travel time of the passing vehicle;

wherein the traffic estimation module for computing an average speed and the average travel time of at least the vehicle on at least the road segment at the given time, comprising;

collecting at least one of the plurality of mobile spot values of the vehicles passing the road segment at the given time, and the plurality of detected spot values of detection of wireless enabled objects in the vehicles passing the road segment at the given time;

filtering undesirable spot values of at least one of the plurality of mobile spot values and the plurality of detected spot values for obtaining matched values of at least one of the plurality of mobile spot values and the plurality of detected spot values;

computing travel time of matched values of at least one of the plurality of mobile spot values and the plurality of detected spot values;

removing outliers; and

computing the average travel time of the passing vehicle for the road segment,

wherein the spot time window changes from an one computing step to an another computing step according to a congestion level that the road segment is experiencing and from an one road segment to an another road segment according to properties of said road segments, wherein said properties include moving vehicle speed limit of said road segments, number of lines of said road segments, start of said road segments, add end of said road segments,

wherein the central server process at least one of the plurality of mobile spot values and the plurality of detected spot values to estimate road traffic in the road segment at the given time.

2. The system of claim 1, wherein the spot time window for a road segment ‘

s’

at a measurement step ‘

i’

at a time ‘

T’

is a length of a time period during which vehicles crossing the road segment ‘

s’

sent the plurality of mobile spot values that are considered for the estimation of the average travel time in the measurement step ‘

i’

.

3. A traffic estimation method for computing an average speed and travel time at a current time of at least a moving vehicle on at least a road segment, the method comprising the steps of:

receiving at least a first set of spot values from at least one of a plurality of mobile communication units of a plurality of moving vehicles passing at least the road segment at a given time and a plurality of fixed communication units of the road segment at the given time, wherein an each of the first set of spot values is indicating at least a geographical location and a time stamp of at least the moving vehicle on the road segment at the given time;

filtering undesirable spot values of at least the first set of spot values for obtaining matched values of at least the first set of spot values;

computing a spot time window having spot values mapped to at least the road segment;

forming a second set of spot values;

forming a third set of spot values from remaining spot values of the second set of spot values;

computing at least a travel time for at least the moving vehicle using the spot values which are in the third set of spot values;

computing an average travel time on the road segment from the travel time for at least the moving vehicle using the spot values which are in the third set of spot values;

computing a variance by using the average travel time on the road segment and the travel time for each moving vehicle using the spot values which are in the third set of spot values;

computing a minimum and a maximum value of acceptable travel time for the road segment;

forming a fourth set of spot values by selecting the spot values from the third set of spot values whose corresponding travel times are within a range of the minimum and the maximum value of acceptable travel times for the road segment including the minimum value and the maximum value;

checking whether number of spot values in the fourth set of spot values is more than a predefined minimum number of spot values required for computing the average speed and travel time of the road segment;

filtering undesirable spot values of the fourth set for matching between spot values of at least one of the plurality of mobile spot values and the plurality of detected spot values;

computing travel time of matched values of spot values;

removing outliers;

calculating the average speed and travel time of the road segment; and

repeating the above steps of the method for another time stamp, if the number of spot values in the fourth set of spot values is not more than a predefined minimum number of spot values required for computing the average segment travel time of the road segment,

wherein at least the mobile communication units installed in vehicles passing the road segment at the given time sends the plurality of mobile spot values to a central server;

wherein at least the fixed communication units installed for detecting wireless enabled objects in vehicles passing the road segment at the given time sends the plurality of detected spot values to the central server;

wherein the spot time window extracts from a database of the central server the plurality of spot values mapped to every road segment for computing the average travel time of the passing vehicle for the road segment,

wherein the plurality of spot values representing vehicles travelling on a road are used for computing the average speed and travel time,

wherein at least a start geographical location and an end geographical location are adapted on the road segment for computing said average speed and travel time,

wherein the first set of spot values are received from at least one of said moving vehicle and the road side units report collected information from on-board units in case of a connected vehicle system.

4. The method of claim 3, wherein each of the spot value indicating at least one of a geographical location and a time stamp of the vehicle on the road segment.

5. The method of claim 3, wherein the spot time window is a length of time period during which moving vehicles crossing the road segment have sent spot values which are falling within the spot time window for the estimation of the average travel time in a current measurement steps of the method.

6. The method of claim 3, wherein the second set of spot values is formed by selecting each spot value from the first set of spot values which were received within the current time and a time defined by the current time minus the spot time window.

7. The method of claim 3, wherein an estimated travel time tt_i,s^(k) of a vehicle ‘

i’

in a road segment ‘

s’

at a measurement step ‘

k’

is computed as

8. The method of claim 7, wherein said remaining spot values of the second set of spot values obtained by the steps of:

removing the spot values from the second set of spot values which have reported at least a first geographical location and a last received geographical location for said moving vehicle such that distance between the first and the last received geographical location for said moving vehicle is less than a predefined fraction of the distance between the start and the end geographical location of the road segment; and

removing the spot values from the second set of spot values which have reported the last received geographical location for the vehicle, that is more than a predefined distance from the end geographical location of the road segment.

9. The method according to claim 3, wherein the step of forming the third set of spot values includes keeping the spot values from the second set of spot values, which correspond to vehicles such that at least one of the geographical location of its last recorded spot value falls after the end geographical location of the road segment.

10. The method according to claim 3, wherein the step of forming the third set of spot values includes keeping the spot values from the second set of spot values, which report to zero value of speed.

11. The method of claim 3, wherein the fourth set of spot values is formed by selecting the spot values from the third set of spot values whose corresponding travel times are within a range of the minimum and the maximum value of acceptable travel times for the road segment including both the values.

12. The method of claim 3, wherein the average segment travel time of the road segment is calculated by using the corresponding travel times of the spot values of the fourth set of spot values.

13. The method according to claim 3, wherein the step of receiving spot values from the vehicles includes receiving spot values from a list including a GPS tracking device on the vehicle, a GPS-equipped mobile device in the vehicle or any traffic sensor like a Bluetooth sensor installed on the road segment or any combination thereof.

14. The method according to claim 13, wherein the spot value received from the GPS tracking device includes at least one of a GPS data record with a time, a latitude, a longitude, a speed or any combination thereof.

15. The method according to claim 13, wherein the spot value received from the Bluetooth sensor installed on the road segment includes at least one of a detection of Bluetooth device of the vehicle, an identifier, an entry time, an exit time, a class of device, a speed of the vehicle at a given time or any combination thereof.

16. The method according to claim 13, wherein the step of forming the third set of spot values includes keeping the spot values received from the Bluetooth sensor installed on the road segment.

17. The method according to claim 13, wherein computing of the average segment travel time will be done after every predefined update time.

18. The method according to claim 3, wherein the spot time window depends on values of at least one of an average speed in the road segment computed during last measurement period, a free flow speed in the road segment, a minimum and a maximum predefined value of the spot time window or any combination thereof.

19. The method according to claim 18, wherein a minimum predefined value of the spot time window is adapted between 10 seconds to 10 minutes.

20. The method according to claim 3, wherein the computing of the average segment travel time will be done at a timestamp higher or equal to the current time plus a maximum delay taken by the spot value between its generation, reception, processing, and storage in the database.

21. The method according to claim 3, wherein a predefined fraction of the distance between the start geographical location and the end geographical location of the road segment is at least 0.8.

22. The method according to claim 3, wherein the predefined distance from the end geographical location of the road segment is adapted between 10 meters to 1000 meters.

23. The method of claim 3, wherein the spot time window for a road segment ‘

s’

at a measurement step ‘

i’

at a time ‘

T’

is a length of a time period during which vehicles crossing the road segment ‘

s’

sent the plurality of mobile spot values that are considered for the estimation of the average travel time in the measurement step ‘

i’

.