A city surveillance system based on floating car system is a promising technique for resilient city management. A floating car system can compose a volatile and efficient fabric for a sustainable city. We examine two kinds of extension on a normal floating car system. The one is a radar-assisted floating. The other is a proactive route search in which each floating car proactively inform their route to the center. We confirmed how these extensions contribute to both sensing coverage and traffic efficiency. The result encourages a floating car center operator can harvest higher coverage sensing data without extending contributor’s travel time
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A proactive route search method for an efficient city surveillance
1. ITS World Congress 2014
A proactive route search method
for an efficient city surveillance
Osamu Masutani
Denso IT Laboratory, Inc.
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Copyright (C) 2014 DENSO IT
LABORATORY,INC.
All Rights Reserved.
2. Summary
Background : City surveillance and FCD
Sensing coverage for city surveillance
Method 1 : Radar-assisted FCD
Method 2 : Proactive route guidance
Conclusion & future work
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LABORATORY,INC. All Rights Reserved.
3. Background : ITS for Smart City
ITS has potential to be an important fabric for sustainable smart city
Power train with less environmental impact
Efficient traffic management
Alternative way to monitor urban environment
City surveillance by vehicle
Key feature for smart city management
Crowd sourcing is promising = FCD
Denso Technical Review
https://www.denso.co.jp/ja/aboutdenso/technology/dtr/v16/files/14.pdf
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Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
4. Key performance indices for city surveillance
KPI for city surveillance by FCD :
Sensing quality (Accuracy)
Quality sensors
Sensing quantity (Coverage)
Number of sensors
Trajectory of sensors = routing
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Number of satellites
Trajectory (orbit) of satellites
Coverage
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
5. Enhancement of coverage by environment sensor
Utilize environment sensor in vehicle
In some scenario, detection of surrounding vehicle virtually be able
to increase data points of sensing
Camera, Radar, Lidar, etc..
Radar-assisted FCD
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Denso Technical Review
https://www.denso.co.jp/ja/aboutdenso/technology/dtr/v17/files/10.pdf
http://www.embedded.com/print/4011081
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
6. Enhancement of coverage by proactive routing
Route control can dispatch each floating car efficiently
By dispersing their routes in the city
Can floating car be controlled by center ? – Yes !
In-direct traffic control (Signs, navigation)
Fleet management
Automated car
Proactive route search
Probing Route control
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Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
7. Core simulation function is available as
Metro traffic simulator
Evaluation environment
Traffic simulation with a simple setting
Simple micro simulation
Grid map, One way traffic
City surveillance target : Traffic (Volume, Speed)
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LABORATORY,INC. All Rights Reserved.
8. Evaluation 1 : Rader Assisted FCD (R-FCD)
Adaptive cruise control system can measure surrounding vehicles
Traffic volume and relative speed can be estimated
Evaluation
How radar leverage data points compared to conventional FCD ?
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9. Evaluation 1 : Result - observation coverage
R-FCD produce much
higher coverage than
conventional FCD
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Link ID
time
Traffic Volume
Full observation
FCD (10%)
R-FCD (10%)
Example Link
time
Volume
Observed traffic volume ratio
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
10. Evaluation 1 : Result - Link travel time estimation
Higher link coverage
yields higher accuracy of
link travel time
estimation
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Link ID
time
Link Travel Time
Full observation
FCD (10%)
R-FCD (10%)
Example Link
time
Travel TIme
Estimation error
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
11. Evaluation 2 : Proactive route search
Each FC reserves route before it arrives
Find optimal route according to number of reservations
Reserve each link on the route
Implementation
Telematics-based navigation
Path prediction
Connected - automated driving
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LABORATORY,INC. All Rights Reserved.
12. Evaluation 2 : Evaluation spec
Indices
Coverage
Travel time
Compared with conventional route
search methods
Static (distance cost)
Reactive (current traffic)
Proactive (reservation)
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20
15
10
5
0
Static
Reactive
Proactive
1000 2000 3000 4000 5000
# of congested links
Simulation Steps
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
13. Evaluation 2 : Result - both indices are improved
Coverage is increased
Travel time is reduced
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Traffic Volume Link ID
Distance
Reactive
Proactive
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
14. Evaluation 2 : Result - Trade-off
Trade-off between coverage and
travel time
In this case, traffic dispersion also
carries reduction of traffic congestion
The effect of reduction of traffic
congestion compensate extension of
travel distance.
Relation between coverage and average travel time
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Better
Distance
Reactive
Worse
300 400 500 600
Coverage
Average Travel Time [sec]
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LABORATORY,INC. All Rights Reserved.
15. Conclusion and Future work
Both of two active sensing methods can enhance FCD
Radar assisted FCD can dramatically increase data amount
Proactive route search can also increase sensing area coverage without extending
travel time of each car
Future work
More realistic evaluation (real city, real traffic)
More dynamic situation (dynamic sensing target)
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17. Appendix – Scalability : traffic demand
Proactive route search enhance more in congested time
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Coverage
Traffic demand [volume/hour] Traffic demand [volume/hour]
Travel time [sec]
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LABORATORY,INC. All Rights Reserved.
18. Appendix – Scalability : trip length
Proactive route search can be applicable for short trip
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Distance
RealTimeTravelTime
RealTimeVolume
Predicted
Map length [blocks]
Coverage
Copyright (C) 2014 DENSO IT
LABORATORY,INC. All Rights Reserved.
Editor's Notes
Hello everyone I am Osamu Masutani from Dnso IT Laboratory, Inc. in Japan.
Our company is a subsidiary company of Denso whose mission is developing and evaluating advanced software tehcnologies.
Today I’ll present you about a proactive route search method for an efficient city surveillance.
Here is a summary of today’s presentation.
First of all I’ll show you the background of this project.
And I’ll briefly explain about sensing coverage for city surveillance
And then I’ll show you two kind of methods to enhance sensing coverage.
First one is radar-assited FCD and second one is a proactive route guidance.
Finally I’ll conclude these work and show future work
Let me introduce background of this project. These technologies helps not only traffic system but also whole city. ITS has potential to be an important fabric for sustainable smart city. For example power train with less einvironmental impact , efficient traffic management or alternative way to monitor urban environment can be important role of sustainable smart city. We focused on third element or city surveillance by vehicle. This is a key feature for smart city management and in this field crowd sourcing is promising technique.
Key performance index for city surveillance consists of two aspects. Sensing quality and sensing quantity. Sensing quality is mainly affected by quality of sensors. Sensing quantity is mainly affected by both number of sensors and trafectory of sensors.
To enhance coverage we first utilize environment sensor in vehicle. In some scenario, detection of surrounding vehicle can to virtually increase data points of sensing. We introduce radar-assisted FCD in this work.
And secondly we introduce proactive routing to enhance coverage. Route control can dispatch each floating car efficiently by dispersing their routes in the city. Fleet management system, traffic signs and car navigation can provide controllability to floating car. Upon these assumption we introduce proactive route search method.
Let me introduce our evaluation environment. We examine traffic simulation with simple setting micro simulation. We employ grid map and one way traffic. And our city surveillance target is traffic itself in this work.
We evaluate radar assisted FCD. In adaptive cruise control system already have enough specification for this. Traffic volume and relative speed can be estimated. We confirm how radar leverage data points compared to conventional FCD.
Here is first result. We calculate observation coverage of r-FCD and conventional FCD. R=FCD produce much higher coverage than FCD. This is observed traffic volume ratio on full traffic.
This is the other result. We evaluate link travel time of each link from each traffic data. R-FCD has much less error than conventional one.
Next we introduce second technique. In proactive route search each floating car reserves route before it arrives there. At first the vehicle query route to traffic center, then traffic enter answer optimal route according to reservations, and vehicle reserve the each links on the route.
We can implement this on telematics service or path prediction system on ADAS or connected automated driving system.
Here is evaluation specification of proactive route search. There are two indices coverage and travel time here. And we compared these three route search static means distance based search reactive means current traffic based search and proactive means reservation based search. Instant result shows proactive route search has effect of reduction of congestion.
This result shows time-space traffic volume plot. With distance based search traffic concentrate to some main arterial links then heavily congested. With reactive search traffic congestion seems to be moved but is not avoided. With proactive search congestion seems to be eliminated. So average travel time is lowest with proactive route search. Proactive route also provide high coverage.
Naturally said trade-off exist between coverage and travel time. Traffic dispersion which is conducted by de-touring brings extension of travel time. However in this simulation setting, traffic dispersion also carries reduction of traffic congestion. The effect of reduction of traffic congestion compensate extension of travel distance.
Let me conclude my presentation. I introduced two active sensing methods and confirm their effect of enhance FCD coverage. Radar assisted FCD can dramatically increase net amount of floating car data. Proactive route search can also increase sensing area coverage without extending total travel time.
For future work we will try more realistic simulation using real city , traffic data . And try to extend our method more dynamic situation.