Predictive automatic incident detection using automatic vehicle identification

• US 7,145,475 B2
• Filed: 03/14/2001
• Issued: 12/05/2006
• Est. Priority Date: 03/15/2000
• Status: Expired due to Term

• Current Assignee: Vertex Aerospace, LLC
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Kavner, Douglas M.
• Primary Examiner(s): Lieu, Julie Bichngoc
• Application Number:
  US09/805,849
• Publication Number:
  US 20020000920A1
• Time in Patent Office: 2,092 Days
• Field of Search: 340/934, 340/905, 340/933, 340/937, 235/384, 701/117, 701/118, 701/119
• US Class Current: 340/933
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions
• CPC Class Codes: G08G 1/164 Centralised systems, e.g. external to vehicles

Abstract

A system and method for detecting incidents along a roadway are provided. A plurality of readers are spaced at intervals along a roadway for reading uniquely identified data from each of a plurality of vehicles. These readings are correlated to obtain information on each of the vehicles and to determine the number of vehicles potentially affected by incidents along the roadway. Finally, the number of each of the vehicles potentially affected by incidents is compared to a sample threshold in order to determine if a traffic incident has occurred.

Claims

1. A method of detecting an incident along a roadway, comprising the unordered steps of:

arranging a plurality of readers at intervals along a roadway for reading uniquely identified data from each one of a plurality of vehicles;

correlating the data with previously read data to obtain information regarding each one of the plurality of vehicles;

determining the number of vehicles potentially affected by incident along the roadway; and

comparing the number of vehicles potentially affected by the incident to a sample threshold.

2. The method of claim 1, wherein the plurality of readers comprises a plurality of traffic probe readers.

3. The method of claim 1, wherein each one of the plurality of readers is spaced at least five kilometers from an adjacent reader.

4. The method of claim 1, wherein the information regarding each one of the plurality of vehicles comprises at least one of:

a vehicle speed;

an expected vehicle travel time for a vehicle to travel between two adjacent readers;

or

an expected arrival time a vehicle to arrive at one of the plurality of readers.

5. The method of claim 1, wherein the step of determining the number of vehicles potentially affected by the incident comprises the step of determining an expected arrival time for each one of the plurality of vehicles to be detected by a particular one of the plurality of readers.

6. The method of claim 5, wherein the step of determining the number of vehicles potentially affected by the incident further comprises the steps of:

determining an amount of time each one of the plurality of vehicles is overdue past the expected arrival time; and

comparing the amount of time each one of the plurality of vehicles is overdue to a predetermined threshold.

7. The method of claim 6, wherein the predetermined threshold is adjusted according to the roadway usage.

8. The method of claim 5, wherein the step of determining the number of each one of the plurality of vehicles potentially affected by the incident further comprises the steps of:

determining an amount of time each one of the plurality of vehicles arrives earlier than the expected arrival time; and

comparing the amount of time each one of the plurality of vehicles arrives early to a predetermined threshold.

9. The method of claim 8, wherein the predetermined threshold is adjusted according to the roadway usage.

10. The method of claim 1, further comprising detecting an incident in response to the number of the vehicles potentially affected by the incident exceeding the sample threshold.

11. The method of claim 10, wherein some of the number of vehicles potentially affected by the incident are overdue at a particular one of the plurality of readers.

12. The method of claim 10, wherein some of the number of vehicles potentially affected by the incident arrive early at a particular one of the plurality of readers.

13. The method of claim 10, wherein the number of vehicles potentially affected by the incident is counted over a predetermined time interval.

14. The method of claim 4, wherein the expected arrival time is a function of a vehicle type.

15. The method of claim 1, wherein the plurality of readers comprise respective transponder readers.

16. The method of claim 1, wherein the plurality of readers comprise respective license plate readers.

17. The method of claim 1, wherein the determining the number of vehicles potentially affected by the incident comprises determining an instantaneous speed of some of the plurality of vehicles.

18. The method of claim 5, wherein the expected arrival time for each one of the plurality of vehicles is calculated by:

$\begin{array}{c}\mathrm{ExpSpeed}<br><br>\left[V_i,S_j\right]=\min <br><br>\left(\mathrm{StartSpeed}<br><br>\left[V_i,S_j\right],\mathrm{HighSpeed}<br><br>\left[S_j\right]\right)\\ \mathrm{ExpTime}<br><br>\left[V_i,S_j\right]=\frac{\mathrm{Length}<br><br>\left[S_j\right]}{\mathrm{ExpSpeed}<br><br>\left[V_i,S_j\right]}\end{array}$

where,

V_i is a vehicle entering a roadway segment Sj;

ExpTime[V_i,S_j]=expected arrival time for the vehicle V_i;

StartSpeed[V_i,Sj]=starting speed of the vehicle V_i at the beginning of the roadway segment S_j;

ExpSpeed[V_j,S_j]=expected speed of the vehicle V_i over the roadway segment S_j;

HighSpeed [S_j]=average legal speed limit over the roadway segment S_j; and

Length [S_j]=length of the roadway segment S_j.

19. The method of claim 18, wherein an overdue time for each one of the plurality of vehicles, is calculated by:

$\mathrm{Overdue}<br><br>\left[V_i,S_j,t_c\right]=\frac{t_c-\mathrm{StartTime}<br><br>\left[V_i,S_j\right]-\mathrm{ExpTime}<br><br>\left[V_i,S_j\right]}{\mathrm{ExpTime}<br><br>\left[V_i,S_j\right]}\times <br><br>100<br><br>\%$

where,

StartTime[V_i,Sj]=time that the vehicle V_i entered the roadway segment S_j.

20. The method of claim 18, wherein a difference between the expected arrival time and an actual segment travel time for each one of the plurality of vehicles is calculated by:

$\mathrm{Diff}<br><br>\left[V_i,S_j\right]=\frac{\begin{array}{c}\max <br><br>\left(\mathrm{ActualTime}<br><br>\left[V_i,S_j\right],\frac{\mathrm{Length}<br><br>\left[S_j\right]}{\mathrm{HighSpeed}<br><br>\left[S_j\right]}\right)-\\ \mathrm{ExpTime}<br><br>\left[V_i,S_j\right]\end{array}}{\mathrm{ExpTime}<br><br>\left[V_i,S_j\right]}\times <br><br>100<br><br>\%;<br><br>$

where;

ActualTime[V_i,Sj]=actual segment travel time for the vehicle V_j to travel over the roadway segment S_j.

21. The method of claim 18, wherein the starting speed of the vehicle V_i at the beginning of the roadway segment S_j is calculated by:

StartSpeed[V_i,Sj]=average speed of the vehicle V_i over a prior roadway segment.

22. The method of claim 18, wherein the starting speed of the vehicle V_i at the beginning of the roadway segment S_j is calculated by:

StartSpeed[V_i,S_j]=instantaneous speed of the vehicle V_i at the beginning of the roadway segment S_j.

23. The method of claim 1, further comprising the step of excluding a vehicle, which is overdue by more than a predetermined time cutoff threshold measured from a time that the vehicle is initially overdue, from being included in the number of vehicles potentially affected by the incident.

24. The method of claim 1, further comprising the step of excluding a vehicle, which has arrived early at the end of a roadway segment by more than a predetermined time cutoff threshold measured from a time that the vehicle is initially early, from being included in the number of vehicles potentially affected by the incident.

25. The method of claim 1, further comprising the step of suppressing the detection of the incident along the roadway when the number of vehicles exiting a segment of the roadway on an off-ramp over a predetermined interval of time exceeds a predetermined threshold.

26. A method for detecting an incident along a roadway, comprising the unordered steps of:

arranging a plurality of traffic probe readers at intervals along the roadway for reading a respective transponder disposed on each one of a plurality of vehicles;

correlating transponder readings from each one of the plurality of vehicles with expected readings associated with each one of the plurality of vehicles at more than one traffic probe reader to obtain at least one of a count of overdue vehicles or a count of early arriving vehicles; and

detecting the incident, which results in an interruption to the flow of traffic, in accordance with the correlating.

27. The method of claim 26, further comprising the step of writing time and location data into the transponder of each one of the plurality of vehicles.

28. The method of claim 26, further comprising the step of arranging a plurality of toll gateways at intervals along a roadway for reading a respective transponder ID from a respective transponder disposed on each one of the plurality of vehicles and for determining the presence of vehicles not having a transponder.

29. An incident detection system comprising:

a traffic management center processor connected to a data network;

a plurality of unique vehicle data readers connected to said data network such that uniquely identified data are read from each one of a plurality of vehicles;

a correlation processor, wherein said uniquely identified data are correlated to obtain at least one of a count of overdue vehicles or a count of early arriving vehicles; and

an incident detection processor coupled to the correlation processor and adapted to compare at least one of the count of overdue vehicles to a first sample threshold or the count of early arriving vehicles to a second sample threshold.

30. The system of claim 29 wherein said plurality of unique vehicle data readers comprise at least one of:

a plurality of traffic probe readers, each one of said plurality of traffic probe readers having unique vehicle identification on reader;

or

a plurality of toll gateways, each one of said plurality of toll gateways having a unique vehicle identification reader.

31. The system of claim 30 further comprising a plurality of roadside toll collection devices coupled to said plurality of toll gateways, coupled to said plurality of traffic probe readers, and coupled to said traffic management center, such that a volume of data transmitted to said traffic management center is reduced.

32. The system of claim 29 wherein said correlation processor is connected to said traffic management center processor.

33. The system of claim 29 wherein said correlation processor is connected to said plurality of unique vehicle data readers.

34. The system of claim 29 wherein said incident processor is connected to said traffic management center processor.

35. The system of claim 29 wherein said incident processor is connected to said plurality of unique vehicle data readers.

36. The apparatus of claim 29, wherein said incident detection processor is further adapted to determine an amount of time each one of the overdue vehicles is overdue past an expected arrival time, and to compare the amount of time each one of the overdue vehicles is overdue to a predetermined threshold.

37. The apparatus of claim 29, wherein said incident detection processor is further adapted to determine the amount of time each one of the early arriving vehicles is early with respect to an expected arrival time, and to compare the amount of time each one of the early arriving vehicles is early to a predetermined threshold.