the practical side of cell phones as traffic probesalaink/orf467f07/cellphoneprobes.pdf ·...
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The Practical Side of Cell Phones as Traffic Probes
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Cell Probe TechnologyPart of general trend away from fixed sensors toward vehicle-based informationReflects frustration with high costs and slow pace of deployment for traditional sensorsMore than just ITS - a broad management and planning tool (see NCHRP report)Characteristics:
Low costfull regional coverageperformance-based, and self sufficient business model
Cell Probe TechnologyPractical success requires more than cell phonesCell phone movement based on cell location and “hand-offs” from one cell to anotherPattern recognition techniques filter out data from those not on the highwayThen traffic algorithms generate travel times and speeds on roadway linksCell phones need to be turned on, but not necessarily in useFull regional systems in place in Baltimore, Antwerp, and Tel Aviv = 4,600 miles
Cell Probe Technology
GSM
SampleObserverSampleSam ple
ObserverObserver
Cell
Cell
Cell
D irectionof travel
GSMGSM
SampleObserverSampleSam ple
ObserverObserver
Cell
Cell
Cell
D irectionof travel
Cell Probe Privacy
Speeds on road links
Personal cellular
position data
Estimotion sample
observer
Estimotion traffic
situation
ITIS publishing
systems
Cellular network operator
Cellular network operator ITISITIS
Firewall
Speeds on road links
Personal cellular
position data
Estimotion sample
observer
Estimotion traffic
situation
ITIS publishing
systems
Cellular network operator
Cellular network operator ITISITIS
Firewall
Handset 49, part 1
Handset 49, part 2
Handset 49, part 3
Handset 49, part 4
Handset 49, part 5
Handset 49, part6
Handset 49, full trip
Handset 49, full trip
Path-Finding Drive TestsHandset 47Handset 47 Handset 52Handset 52
Handset 49Handset 49 GPS TrackGPS Track
(b)(a)
(c) (d)
Baltimore MMTISProvides first regional deployment of commercial-quality cellular traffic probes in North AmericaMutually profitable public-private partnership
Test commercial markets during projectIntegrate with existing public data – including transit and E-911Encourage public applications beyond traditional ITS
Contract signed September 2004; data flow to Maryland DOT began April 2005
Baltimore MMTIS – Private Firms
Delcan-NETTransportation and technology consultantsFifty plus years in businessProfitable every year; staff = 500 plus
ITIS HoldingsLeader in traffic probes; staff = 100Commercial customers – 16 automobile firms, for-profit 511Profitable!Publicly traded on London exchange
National cellular firms
MARYLAND DOT CAMERAS SHOW ACCURACY OF TRAFFIC INFORMATION BEING CAPTURED USING CELL PROBES
I-695 at HARTFORD ROADMonday, June 6th 2005
9:02:18 am
I-695 at HARTFORD ROADMonday, June 6th 2005
9:33:06 am
CELL PROBES ACCURATELY UPDATETRAFFIC CONDITIONS AS CHANGES OCCUR
Produced by Dr Hillel Bar Gerd, Associate Professor, Ben Gurion Negev University, Israel
Baltimore Comparison with RTMS Data
Traffic Situation reported by ITIS CFVD™ Technology and RTMS equipmentBaltimore I-695 @ I-70 Inner loop - Friday, August 12
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ITIS CFVD™ data RTMS data
Analysis Route Overview
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Slide 22
a1 This slide gives an overview of the Baltimore ring, and the north-western part which was analysed for this presentationalon, 8/19/2005
Performance data I-695 – July 2005
Baltimore I-695 Weekday Patterns
DistanceTime
CongestionStatus
06:00
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Baltimore I-695 Saturday Patterns
Distance
CongestionStatus
06:00
12:00
Time
Baltimore I-695 Route Travel Time
Journey Time (sec)
Time
Day of week
08:00
18:00May
June
July
Travel time comparisons over a common road sectionRoad section of 1.225 miles on I-695 Baltimore Beltway - junction 22 to 23
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Travel time (seconds)
04-Jul 11-Jul
04th July public holiday profile - no congestion throughout the day11th July normal Monday congestion profile - increased travel times at peak times
Beyond Baltimore
Delcan-NET/ITIS selected to negotiate with Missouri DOT
Statewide system -- 5,500 milesSt. Louis, Kansas City, all Interstates plus important rural roadsCompletion within six monthsEmphasis on performance measures and operations
Conversations with other DOTS
Possible ApplicationsTravel Times
For message signs; web sitesPerformance measures
Include arterial network“Top 10” routesTTI-type reports
Operations planningSpecial eventsWork zone managementEvaluation of actions
SafetyFocus on problem areas and assessments
Port/intermodal accessLocal/regional web sitesStatewide coverage
ApplicationsGeneral Planning and Management
Regional congestion managementArchived data supports system analysis, ”average day” information, long-range planningIntegrated regional or corridor managementPlan for “extreme” or special eventsHomeland security applications – no-notice evacuationsRapid evaluation of alternativesWork zone managementRural planning and operationsTraffic volume estimates -- future
Applications (2)
Performance MeasurementSystem performance in near real timeReliability measures – critical from user’s perspective (travel time index, planning time index, etc.)Performance-based systems – information for operators, users, and the publicCongestion management – support for HOT lanes and other finance alternativesEconomic value from partnerships with business – the DOT a part of just in time delivery
Applications (3)Travel Demand and Air Quality Modeling
Today – Validate travel demand and Mobile6 modelsTomorrow – origin/destination dataTomorrow – New model development: activity-based and beyond
SafetyAnalysis and predictionTargeted deployment of safety personnel
CommunicationPublic participation – real data on congestionNear real-time data – web, PDA, 511Premium 511 service
Applications (4)Freight Operations
Web- or cell-based distribution of roadway informationIndividual dynamic routing recommendations based on congestionTravel time prediction to improve asset utilization
Freight AnalyticsStrategic analysis of freight movement for congestion mitigationOrigin/destination data to examine flows and set prioritiesSupport for cost/benefit and alternatives analysis
Appendix
Safety applicationSome validation results
Safety Example
Operational toolAssign patrol cars to road segments based on:
Average speed – Z percent above speed limitTrigger points – X percent of traffic more than Y percent above speed limit
Identify trends and historical patternsShort-term forecasts
Evaluation tool – near real-timeAssess what worked and how wellStatistical analysis of patterns
Safety ExampleRoad # 5
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Hours
Km
/h
5290
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4918
Speed Limit
Distribution of Speeds
Speed Limit
Safety Example
Validation results
Tel Aviv system – Dr. Hillel Bar Gerd, Associate Professor, Ben GurionUniversityev University, Israel
“The main conclusion of this experiment is that in most cases all three methods (floating vehicle, loop detectors, and the cellular system) provide very similar travel time estimates. In that respect, the cellular system is a reliable method for travel time measurements, suitable for many practical applications.”
Produced by Dr Hillel Bar Gerd, Associate Professor, Ben Guion Negev University, Israel
Comparison to GPS
Loop detectors
CFVD™
0.90 min0.49 min
1.13 min1.25 minRMS
Bias
1.34 min 1.44 minAccuracySQRT(Bias2+RMS2)
Produced by Dr Hillel Bar Gerd, Associate Professor, Ben Guion Negev University, Israel