od estimation using mobile phone call records
DESCRIPTION
In this research, we propose a methodology to develop OD matrices using mobile phoneCall Detail Records (CDR) and limited traffic counts. CDR, which consist of time stampedtower locations with caller IDs, are analyzed first and trips occurring within certain timewindows are used to generate tower-to-tower transient OD matrices for different time periods.These are then associated with corresponding nodes of the traffic network and convertedto node-to-node transient OD matrices. The actual OD matrices are derived byscaling up these node-to-node transient OD matrices. An optimization based approach, inconjunction with a microscopic traffic simulation platform, is used to determine the scalingfactors that result best matches with the observed traffic counts. The methodology is demonstratedusing CDR from 2.87 million users of Dhaka, Bangladesh over a month and trafficcounts from 13 key locations over 3 days of that month. The applicability of the methodologyis supported by a validation study.TRANSCRIPT
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Development of Origin-Destination
Matrices Using Mobile Phone Call Data
Md Shahadat Iqbal, BUET
Charisma F Choudhury, UoL
Pu Wang, MIT
Marta Gonzalez, MIT
Bangladesh University
of Engineering and
Technology
Massachusetts
Institute of
Technology
University of
Leeds
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Data sources Motivation
Traditional approaches of developing OD matrices rely on roadside and
household surveys, and/or traffic
counts
Limited sample sizes
Prone to sampling biases, non-response bias and reporting errors
Lower update frequencies
High data collection costs
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Mobile phone CDR Mobile Phone CDR
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Mobile phone CDR Mobile Phone CDR
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Coarse granularity
May not be the final origin/destination
Only transient ODs (t-Ods)
False displacements
Penetration and user bias
Location bias
Data 2: Call Detail Records
Mobile phone CDR Challenges
B (t-O)
C
A (O)
D
F (D)
E (t-D)
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Proposed framework
Actual OD = t-OD * penetration factor * phone usage
factor * vehicle usage factor
Scaling factor adjusted to match ground truth (traffic counts)
- Microsimulation tool
Framework
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Proposed framework
Convert tower-to-tower
transient OD to node-to-
node transient OD
Determine scaling factor
using simulator
CDR data
Traffic count data
Network data
Generate tower-to-tower
transient OD matrix
Actual OD matrix
Mobile phone CDR Proposed Framework
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Study area
Central part of the Dhaka city
- Area: 300km2 , Pop.:10.7million
- No automated data collection
system in place
Mobile phone penetration rate more than 90%
Calls from 6.9 million users (65% of the population of the
study area) over a month
- 971.33 million anonymized call records
Mobile phone CDR Case Study
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Step 1: Generate tower-to-tower t-OD Step 1: Generate Tower-to-tower t-OD
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Step 2: Convert to node-to-node t-OD
Step 2: Convert to Node-to-Node t-OD
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Step 2: Convert to node-to-node t-OD
Step 2: Convert to Node-to-Node t-OD
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Step 3: Determine scaling factor
t-OD from step 2 Seed OD in MITSIMLab
Scaled up using an optimization based approach
Step 3: Determine Scaling Factor
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Step 3: Determine scaling factor Step 3: Determine Scaling Factor
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Step 3: Determine scaling factor Step 3: Determine Scaling Factor
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Results 7:00-9:00
t-OD actual OD
Results
7:00-9:00
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Validation
Scaled up ODs have been applied to simulate the traffic between 9:00-12:00 in MITSIMLab
Simulated traffic counts are compared against the observed counts from these locations on a different day
- Root Mean Square Error 335.09
- Root Mean Square Percent Errors 13.59%
Validation
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Summary
Mobile phone CDR and limited traffic count data can be successfully combined to generate OD matrices
More economic than the traditional approaches (CDR already recorded for billing purposes)
Convenient for periodic update of the OD matrix
Extendable for dynamic OD estimation
Particularly effective for generating complex OD matrix where land use pattern is heterogeneous and asymmetry in
travelling pattern prevails throughout the day but there is a
limitation of traditional data sources
Summary
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Session 842
Forthcoming issue of Transportation Research Part C
Email: [email protected]
Questions?