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A Method for
Sharing Traffic Jam Information
using Inter-Vehicle Communication
Naoki Shibara, Takashi Terauchi*, Tomoya Ki...
2July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Background
 $100 billion/year of economic loss by traffic jam
 Existing s...
3July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Purpose of the study
 Autonomous collection of statistical traffic info.
...
4July 21, 2006 V2VCOM 2006 - N. Shibata et al.
A1 A2 A3
A6A5A4
A7 A8 A9
Overview of the method (1/2)
The map is divided in...
5July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Overview of the method (2/2)
 Arrival time can be estimated by summing up
...
6July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Outline
 Step 1. Collection of traffic info.
 Collecting time to pass thr...
7July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Challenges for accuracy
 Distinguishing time between turning
right/left an...
8July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Problem of per-link measurement
• How can time to turn right/left and go
st...
9July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Per-area measurement
Collecting data for each combination of
incoming and o...
10July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Time to pass through area
Measuring time for each combination of two
links...
11July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Outline
 Step 1. Collection of traffic info.
 Collecting time to pass th...
12July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Area border
Exchanging info. between cars
 When a car crosses area border...
13July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Adjacent areas The original area the
info is generated at
Retention and di...
14July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Retention and disposal of data
Here, this car
disposes info.
• Info. for a...
15July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Outline
 Step 1. Collection of traffic info.
 Collecting time to pass th...
16July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Redundant counting of same data
 Average area passage time to be obtained...
17July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Avoiding the problem
 Avoiding redundant processing of area
passage time
...
18July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Avoiding redundant counting
5 sets of data7 sets of data
AA
19July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Avoiding redundant counting
AA
If a same set of data is included in the
re...
20July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Exchanging data between cars
The case when threshold C = 10
5 sets of data...
21July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Exchanging data between cars
The case when threshold C = 10
5 sets of data...
22July 21, 2006 V2VCOM 2006 - N. Shibata et al.
AA
Avoiding redundant processing of stat. data
 Each stat. data include h...
23July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Outline
 Step 1. Collection of traffic info.
 Collecting time to pass th...
24July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Exchanging information
 All information cannot be exchanged due to
bandwi...
25July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Evaluation
 Experiment 1
 Gain of accuracy by avoiding redundant process...
26July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Common configurations
 Area size 300 m×300 m
 Radio range 100 m
 Max sp...
27July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Traffic simulator :NETSTREAM by TOYOTA
Map size :1.2km×1.2km
The number of...
28July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Gain of accuracy by
avoiding redundant processing
0
20
40
60
80
100
120
A ...
29July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Gain of accuracy by
prioritized data transmission
0
20
40
60
80
100
A B C ...
30July 21, 2006 V2VCOM 2006 - N. Shibata et al.
0
20
40
60
80
100
120
140
(A,O) (B,P) (C,Q) (D,R) (E,S) (F,T) (G,U)
(Area ...
31July 21, 2006 V2VCOM 2006 - N. Shibata et al.
Conclusion
 We proposed an autonomous collection
method for traffic infor...
Shibata, N., Terauchi, T., Kitani, T., Yasumoto,
K., Ito, M., Higashino, T.: A Method for
Sharing Traffic Jam Information ...
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(Slides) A Method for Sharing Traffic Jam Information Using Inter-Vehicle Communication

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Shibata, N., Terauchi, T., Kitani, T., Yasumoto, K., Ito, M., Higashino, T.:
A Method for Sharing Traffic Jam Information Using Inter-Vehicle Communication, The 2nd International Workshop on Vehicle-to-Vehicle Communications (V2VCOM) (Mobiquitous2006 Workshop), (July 2006) , pp. 1-7, DOI:10.1109/MOBIQ.2006.340428 (invited paper).

http://ito-lab.naist.jp/themes/pdffiles/060725.shibata.v2vcom06.pdf

Veröffentlicht in: Technologie, Business
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(Slides) A Method for Sharing Traffic Jam Information Using Inter-Vehicle Communication

  1. 1. A Method for Sharing Traffic Jam Information using Inter-Vehicle Communication Naoki Shibara, Takashi Terauchi*, Tomoya Kitani*, Keiichi Yasumoto*, Minoru Ito* and Teruo Higashino** Shiga University, JAPAN *Nara Institute of Science and Technology (NAIST), JAPAN **Osaka University, JAPAN [ Invited Paper ] The 2nd International Workshop on Vehicle-to-Vehicle Communications 2006 (V2VCOM 2006), 21 July, 2006
  2. 2. 2July 21, 2006 V2VCOM 2006 - N. Shibata et al. Background  $100 billion/year of economic loss by traffic jam  Existing services for alleviating traffic jam  VICS (Vehicle Information and Communication System)  A service provided by Japanese government  Provides traffic jam information of trunk roads  Cyber-Navi (Pioneer)  An advanced car-navigation system  Predicts traffic jam from information in the past  Weaknesses of the existing methods  Service area  Operation cost  Time lag / not up-to-date information
  3. 3. 3July 21, 2006 V2VCOM 2006 - N. Shibata et al. Purpose of the study  Autonomous collection of statistical traffic info.  Using GPS and inter-vehicle communication  No need for costly infrastructures  Prediction of arrival time using the gathered info.  Provides basic car-navigation system functions  Route navigation avoiding congested areas
  4. 4. 4July 21, 2006 V2VCOM 2006 - N. Shibata et al. A1 A2 A3 A6A5A4 A7 A8 A9 Overview of the method (1/2) The map is divided into areas. Granularity of area is decided according to the amount of traffic and road density. Cars measure time to pass through each area using GPS. Traffic info. can be collected by exchanging info. between cars.
  5. 5. 5July 21, 2006 V2VCOM 2006 - N. Shibata et al. Overview of the method (2/2)  Arrival time can be estimated by summing up time to pass through areas A1 A2 A3 A6A5A4 A7 A8 A9 1’20’’ 1’40’’ S D tA7 tA4 tA5 tA2 tA7’ tA8 tA5’ tA2’
  6. 6. 6July 21, 2006 V2VCOM 2006 - N. Shibata et al. Outline  Step 1. Collection of traffic info.  Collecting time to pass through each area  Propagation and retention of collected info.  Avoiding redundant processing of same data  Exchanging data with priorities  Step 2. Estimating arrival time
  7. 7. 7July 21, 2006 V2VCOM 2006 - N. Shibata et al. Challenges for accuracy  Distinguishing time between turning right/left and going straight is crucial  Especially, time needed to turn right is largely influenced by the opposite lane
  8. 8. 8July 21, 2006 V2VCOM 2006 - N. Shibata et al. Problem of per-link measurement • How can time to turn right/left and go straight be distinguished?  Collecting info. on a per-lane basis is hard  Too much data by collecting on a per-link basis
  9. 9. 9July 21, 2006 V2VCOM 2006 - N. Shibata et al. Per-area measurement Collecting data for each combination of incoming and outgoing link  Time to turn at crossings is reflected Area border 24 sec 38 sec
  10. 10. 10July 21, 2006 V2VCOM 2006 - N. Shibata et al. Time to pass through area Measuring time for each combination of two links crossing area border G E A H I B D C F a e d c b Blue links cross area border Red dotted lines are area borders Links Measured time ( a , b ) 150 sec ( a , e ) 220 sec .... For the area at the center, time is measured for each two combination of blue links
  11. 11. 11July 21, 2006 V2VCOM 2006 - N. Shibata et al. Outline  Step 1. Collection of traffic info.  Collecting time to pass through each area  Propagation and retention of collected info.  Avoiding redundant processing of same data  Exchanging data with priorities  Step 2. Estimating arrival time
  12. 12. 12July 21, 2006 V2VCOM 2006 - N. Shibata et al. Area border Exchanging info. between cars  When a car crosses area border, it broadcasts its info  When another car receives this info, it adds the info into its memory  The car continues to broadcast data for some time
  13. 13. 13July 21, 2006 V2VCOM 2006 - N. Shibata et al. Adjacent areas The original area the info is generated at Retention and disposal of data • Info. for an area adjacent to the area a car is running at is retained.
  14. 14. 14July 21, 2006 V2VCOM 2006 - N. Shibata et al. Retention and disposal of data Here, this car disposes info. • Info. for an area adjacent to the area a car is running at is retained. • When a car goes off from these areas, it disposes the corresponding data
  15. 15. 15July 21, 2006 V2VCOM 2006 - N. Shibata et al. Outline  Step 1. Collection of traffic info.  Collecting time to pass through each area  Propagation and retention of collected info.  Avoiding redundant processing of same data  Exchanging data with priorities  Step 2. Estimating arrival time
  16. 16. 16July 21, 2006 V2VCOM 2006 - N. Shibata et al. Redundant counting of same data  Average area passage time to be obtained  Data from multiple cars have to be collected  Data originated from one car is exchanged through many cars, and treated as multiple data A A (A+B)/2 (A+C)/2 (A+A+B+C)/4 ?!
  17. 17. 17July 21, 2006 V2VCOM 2006 - N. Shibata et al. Avoiding the problem  Avoiding redundant processing of area passage time  Measured time by each car is not processed until a car gets a sufficient number of data Then, data are converted to statistical data  Ignore received data if it has a same set of data as data retained.  Avoiding redundant processing of statistical data  Distinguish redundant data by hash value
  18. 18. 18July 21, 2006 V2VCOM 2006 - N. Shibata et al. Avoiding redundant counting 5 sets of data7 sets of data AA
  19. 19. 19July 21, 2006 V2VCOM 2006 - N. Shibata et al. Avoiding redundant counting AA If a same set of data is included in the received data, it's ignored.
  20. 20. 20July 21, 2006 V2VCOM 2006 - N. Shibata et al. Exchanging data between cars The case when threshold C = 10 5 sets of data 7 sets of data
  21. 21. 21July 21, 2006 V2VCOM 2006 - N. Shibata et al. Exchanging data between cars The case when threshold C = 10 5 sets of data7 sets of data C sets of data is converted to one statistical data 10 Remainder
  22. 22. 22July 21, 2006 V2VCOM 2006 - N. Shibata et al. AA Avoiding redundant processing of stat. data  Each stat. data include hash value calculated from car IDs Stat. data A A Compare hash value, and discard if it has already the same data
  23. 23. 23July 21, 2006 V2VCOM 2006 - N. Shibata et al. Outline  Step 1. Collection of traffic info.  Collecting time to pass through each area  Propagation and retention of collected info.  Avoiding redundant processing of same data  Exchanging data with priorities  Step 2. Estimating arrival time
  24. 24. 24July 21, 2006 V2VCOM 2006 - N. Shibata et al. Exchanging information  All information cannot be exchanged due to bandwidth limitation  Data is prioritized based on where the car is running at, and how the areas are congested Mid High High HighMidLow Low Low Mid Position of the car
  25. 25. 25July 21, 2006 V2VCOM 2006 - N. Shibata et al. Evaluation  Experiment 1  Gain of accuracy by avoiding redundant processing  Experiment 2  Gain of accuracy by prioritized data transmission  Experiment 3  Overall accuracy of estimated arrival time
  26. 26. 26July 21, 2006 V2VCOM 2006 - N. Shibata et al. Common configurations  Area size 300 m×300 m  Radio range 100 m  Max speed of cars 16.6 m/s (60 km/h)  Threshold C 5  Size of packet 1500 byte  Max # of packets sent by a car 0.3 packets / sec  Duration of each packet 0.01 sec  Duration of simulation 1 hour  Time to live of info. 30 minutes  Number of cars 300 at maximum
  27. 27. 27July 21, 2006 V2VCOM 2006 - N. Shibata et al. Traffic simulator :NETSTREAM by TOYOTA Map size :1.2km×1.2km The number of nodes : 21 The number of links : 78
  28. 28. 28July 21, 2006 V2VCOM 2006 - N. Shibata et al. Gain of accuracy by avoiding redundant processing 0 20 40 60 80 100 120 A B C D E F G H I Link Pair PassageTime(sec.) No avoidance Our method Actual time If no avoidance, obtained time is much closer to the mode
  29. 29. 29July 21, 2006 V2VCOM 2006 - N. Shibata et al. Gain of accuracy by prioritized data transmission 0 20 40 60 80 100 A B C D E F G H I Link Pair PassageTime(sec.) No prioritizing Our method Actual time Data is lost Only two cars have data Loss of information is avoided by prioritizing
  30. 30. 30July 21, 2006 V2VCOM 2006 - N. Shibata et al. 0 20 40 60 80 100 120 140 (A,O) (B,P) (C,Q) (D,R) (E,S) (F,T) (G,U) (Area 1, Area 2) PassageTime(sec.) Estimated time vs actual time Estimated Actual A1 A2 A O B C P Q
  31. 31. 31July 21, 2006 V2VCOM 2006 - N. Shibata et al. Conclusion  We proposed an autonomous collection method for traffic information  We evaluated our method using the traffic simulator NETSTREAM  Future works include  Dissipating information to further area  Making it works correctly with very few cars on the road
  32. 32. Shibata, N., Terauchi, T., Kitani, T., Yasumoto, K., Ito, M., Higashino, T.: A Method for Sharing Traffic Jam Information Using Inter- Vehicle Communication, The 2nd International Workshop on Vehicle-to-Vehicle Communications (V2VCOM) (Mobiquitous2006 Workshop), pp. 1-7. DOI:10.1109/MOBIQ.2006.340428 [ PDF ] 32July 21, 2006 V2VCOM 2006 - N. Shibata et al.

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