Methods for determining turning rates in a road network

• US 7,894,979 B2
• Filed: 05/24/2006
• Issued: 02/22/2011
• Est. Priority Date: 05/31/2005
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Mück, Jürgen
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Figueroa; Jaime
• Application Number:
  US11/629,796
• Publication Number:
  US 20080069000A1
• Time in Patent Office: 1,735 Days
• Field of Search: 701/1, 701/117, 701/118, 370/229, 370/230, 370/231, 370/232, 370/233, 370/234, 370/235, 340/474, 340/475, 340/476, 340/909, 340/916, 340/934, 340/937, 340/995.13, 404/1, 342/454
• US Class Current: 701/117
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions

Abstract

Methods for determining turning rates in a road network are provided. Traffic volumes are recorded at measurement cross-sections at predefinable measuring intervals. For at least one forward-related subnetwork of the road network in which measurement cross-sections are taken into account at an exit and at entries of the subnetwork, a model equation is formulated in which the exit traffic volume is set as the weighted sum of the entry traffic volumes and the weighting factors correspond to the forward-related turning rates which specify in each case the portion of an entry traffic volume flowing out through the exit taken into account, and wherein the forward-related turning rates are calculated on the basis of the model equation using a mathematical estimation method.

Claims

1. A method for determining turning rates in a road network, comprising:

measuring traffic volumes at plurality of measurement cross-sections at a plurality predefined measuring intervals;

dividing the road network at least partially into subnetworks with entries and at least one exit;

considering at least one subnetwork as a forward-related network;

formulating a model equation for the forward-related subnetwork in which measurement cross-sections are based upon the at least one exit and the entries of the subnetwork;

setting an exit traffic volume as a weighted sum of entry traffic volumes, wherein a weighting factor corresponds to forward-related turning rates, the weighting factor specifying the portion of an entry traffic volume flowing out through the at least one exit;

calculating the forward-related turning rates based upon the model equation;

accounting the entry traffic volumes of the plurality of past measuring intervals in the weighted sum for the exit traffic volume of a predefined measuring interval; and

determining a forward-related turning rate based upon a sum of corresponding turning rates of the measuring intervals,

wherein the model equation is based upon a mathematical estimation method, and

wherein an extended Kalman filter is used in the mathematical estimation method.

2. The method as claimed in claim 1, wherein

at least one subnetwork is a backward-related subnetwork having measurement cross sections at an entry and at exits,

a model equation is formulated in which the entry traffic volume is set as the weighted sum of exit traffic volumes and the weighting factors correspond to a backward-related turning rates specifying in each case the portion of an exit traffic volume that has flowed in through the entry taken into account,

turning rates are calculated by a mathematical estimation method based upon the model equation,

the weighted sum for the entry traffic volume of a given measuring interval is based upon the exit traffic volumes of a plurality of subsequent measuring intervals, and

the backward-related turning rate is based upon the sum of the corresponding turning rates of the measuring intervals.

3. The method as claimed in claim 1, wherein the estimation process is interrupted when a traffic overload is detected at a measurement cross-section.

4. A method for dete mining turning rates at an intersection of a road network, comprising:

measuring traffic volumes at a plurality of measurement cross-sections at a plurality of predefined measuring intervals;

dividing the road network at least partially into subnetworks with entries and at least one exit, wherein at least one part of the subnetwork is at least a part of the intersection;

formulating a model equation for the subnetwork based upon measurement cross-sections at the exit and at the entries of the subnetwork;

setting an exit traffic volume as a weighted sum of entry traffic volumes, wherein a plurality of weighting factors correspond to a plurality of turning rates, the turning rates specifying the portion of an entry traffic volume flowing out through the at least one exit;

calculating the turning rates based upon the model equation which is based upon a mathematical estimation method;

accounting the entry traffic volumes of a plurality of preceding measuring intervals in the weighted sum for the exit traffic volume of a predefined measuring interval; and

determining a turning rate based upon a sum of corresponding turning rates of the measuring intervals,

wherein the model equation is based upon a mathematical estimation method, and

wherein an extended Kalman filter is used in the mathematical estimation method.

5. The method as claimed in claim 4, wherein the subnetwork is a forward related network and the turnings are forward related.

6. The method as claimed in claim 4, wherein the subnetwork is a backward related network.

7. The method as claimed in claim 4, wherein

a traffic stream of a subnetwork between an origin and a destination is determined,

the traffic stream is calculated by only using measurement cross-sections at the edge of the subnetwork, and

the traffic stream is calculated based upon the determined turning rates and recorded traffic volumes.

8. The method as claimed in claim 4, wherein the number of measuring intervals increases with the size of the subnetwork.

9. The method as claimed in claim 4, wherein the measuring intervals are lengthened with an increased size of the subnetwork.

10. A method for determining the traffic volume on a roadway point of a road network, based upon a method for deteimining turning rates in a road network, comprising:

deteimining turning rates by

measuring traffic volumes at a plurality of measurement cross-sections at a plurality of predefined measuring intervals,

dividing the road network at least partially into subnetworks with entries and at least one exit,

considering at least one subnetwork as a forward-related network,

formulating a model equation for the forward-related subnetwork in which measurement cross-sections are based upon the exit and the entries of the subnetwork,

setting an exit traffic volume as a weighted sum of entry traffic volumes, wherein weighting factors correspond to forward-related turning rates, the weighting factor specifying the portion of an entry traffic volume flowing out through the at least one exit,

calculating the forward-related turning rates based upon the model equation,

accounting the entry traffic volumes of the plurality of past measuring intervals in the weighted sum for the exit traffic volume of a predefined measuring interval, and

determining a forward-related turning rate based upon a sum of corresponding turning rates of the measuring intervals;

providing turning rates for a subnetwork of the road network, wherein first access point is based upon a cross-section of the roadway and a second access point is based upon the measurement cross-sections; and

calculating the traffic volume at the cross-section of the roadway at an access point based upon the provided turning rates and the traffic volumes of other access points at the measurement cross-sections,

wherein the model equation is based upon a mathematical estimation method, and

wherein an extended Kalman filter is used in the mathematical estimation method.

11. The method as claimed in claim 10, wherein the access point is an entry.

12. The method as claimed in claim 10, wherein the access point is an exit.

13. The method as claimed in claim 10, wherein the traffic volume determined for the roadway point is used as a substitute value for a defective or failed measurement cross-section.

14. The method as claimed in claim 10, wherein

the traffic volume is used for determining a number of vehicles within a roadway section,

the traffic volume is recorded at the first end point at a measurement cross-section,

the traffic volume is determined at a second end point based upon the number of vehicles in the roadway section, based upon a time integration of the difference between the traffic volume flowing into the roadway section and the traffic volume flowing away from same.

15. The method as claimed in claim 10, wherein a correction factor is used to correct the turning rates.

16. The method as claimed in claim 15, wherein the correction factor is determined by a homogeneous equation system based upon the vehicle conservation of the actual forward- and backward-related turning rates.