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2018 N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP RESEARCH REPORT 868 Cell Phone Location Data for Travel Behavior Analysis Cambridge Systematics, Inc. Chicago, IL w i t h Massachusetts Institute of Technology Cambridge, MA Subscriber Categories Data and Information Technology â¢ Highways â¢ Planning and Forecasting Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research is the most effective way to solve many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide inter- est to highway authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 ini- tiated an objective national highway research program using modern scientific techniquesâthe National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRBâs recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive com- mittee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, univer- sities, and industry; TRBâs relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of special- ists in highway transportation matters to bring the findings of research directly to those in a position to use them. The program is developed on the basis of research needs identified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the Federal Highway Administration. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&Iâs recommendations are proposed to the AASHTO Board of Direc- tors and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Academies and TRB. The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs. Published research reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to http://www.national-academies.org and then searching for TRB Printed in the United States of America NCHRP RESEARCH REPORT 868 Project 08-95 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-39035-4 Library of Congress Control Number 2018906086 Â© 2018 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FRA, FTA, Office of the Assistant Secretary for Research and Technology, PHMSA, or TDC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names appear herein solely because they are considered essential to the object of the report.
The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to increase the benefits that transportation contributes to society by providing leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied committees, task forces, and panels annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.
C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS In NCHRP Project 08-95, the research team evaluated the use of cell phone location data for travel behavior analysis and developed guidelines for practitioners. The team, led by Cambridge Systematics, Inc. staff Kimon Proussaloglou, Daniel Beagan, and Anurag Komanduri, analyzed travel data derived from call detail records (CDRs) and contrasted them with estimates derived from survey data and models to provide practical guidance on the value and uses of CDR data. We want to acknowledge the key research contributions of our colleagues at the Massachusetts Institute of Technology (MIT). The case study analysis and results presented in Chapters 4 through 8 and parts of Chapter 2 were contributed by Professor Marta GonzÃ¡lez and Dr. Shan Jiang and based on their original research and data analysis. The case study also reflects work undertaken in prior studies by Professor GonzÃ¡lez and her research group at MIT. Cambridge Systematics developed the background approach and set the stage for the analysis and the guidelines by adopting a practitionerâs perspective in the summary and Chapters 1 through 3. We contrib- uted to the literature review and added our insights to the case study discussed in Chapters 4 through 8 through the lens of a practitionerâs perspective focusing on the inference of stay activity locations and the practical comparisons presented. Finally, we developed Chapter 9 to distill the findings and develop practical guidance for transportation practitioners. This concluding chapter discusses administrative, data-related, and modeling considerations for using cell phone data and presents recent research aimed at improving the industryâs best practices. CRP STAFF FOR NCHRP RESEARCH REPORT 868 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Lawrence D. Goldstein, Senior Program Officer Anthony P. Avery, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Janet M. McNaughton, Senior Editor NCHRP PROJECT 08-95 PANEL Field of Transportation PlanningâArea of Forecasting Kermit W. Wies, Northwestern University Transportation Center, Evanston, IL (Chair) Rebekah S. Anderson, Ohio DOT, Columbus Tae-Gyu Kim, North Carolina DOT, Raleigh Guy Rousseau, Atlanta Regional Commission, GA Erik E. Sabina, Colorado DOT, Denver Reginald R. Souleyrette, University of Kentucky, Lexington Fang Yuan, Delaware Valley Regional Planning Commission, Philadelphia, PA Sarah Sun, FHWA Liaison Michael L. Cohen, NAS Committee on National Statistics (CNSTAT) Liaison Jennifer L. Weeks, TRB Liaison
NCHRP Research Report 868: Cell Phone Location Data for Travel Behavior Analysis presents guidelines for transportation planners and travel modelers on how to (1) evaluate the extent to which cell phone location data and associated products accurately depict travel; (2) identify whether and how these extensive data resources can be used to improve understanding of travel characteristics and the ability to model travel patterns and behavior more effectively; and (3) support practitionersâ evaluation of the strengths and weaknesses of anonymized call detail record locations from cell phone data. The report includes guidelines for transportation practitioners and agency staff with a vested interest in developing and applying new methods of capturing travel data from cell phones to enhance travel models. This is an emerging field of interest subject to complexi- ties linked to acquiring data and applying these data while maintaining privacy in a complex legal and practical framework. The emergence of these data constitutes a significant oppor- tunity for change in the travel modeling community, with access to detail and volume not previously available. A better understanding of the strengths and weaknesses of these data is an important step in this direction. Information on billions of locations is generated every day from mobile devices. Over the past decade, cell phone location data have become commercially available for trans- portation planning purposes. Mobile signaling can provide a detailed picture showing how people move throughout the day. Cell phone location data used and analyzed in this study correspond to âcall detail records,â which include location information every time a call is made or answered, a text message is sent or received, or the Internet is accessed. Call detail records from cell phone location data offer the potential to provide informa- tion about activity location, frequency of repeated travel, travel outside of a study area, and originâdestination data for travel to special events. This information can be used to model, evaluate, and analyze the flow patterns of both residents and visitors in a given study area. With the emergence of large amounts of data, research is needed to explore and evaluate methods used for processing cell phone location data to generate travel behavior infor- mation and provide guidelines for the use of the information by transportation planning practitioners. In tackling this problem, the research team led by Cambridge Systematics, Inc., with support from the Massachusetts Institute of Technology, had to address a broad range of significant questions to evaluate and test opportunities for use of cell phone data. The study approach used travel in the Boston, Massachusetts, region as a case study to compare and contrast traditional travel survey data and regional models with Census data and with F O R E W O R D By Lawrence D. Goldstein Staff Officer Transportation Research Board
cell phone-derived data describing regional travel characteristics. The questions that were addressed included the following: â¢ What are the best options for using cell phone data for travel estimates in support of modeling techniques? â¢ What are the strengths and weaknesses of cell phone data that can support travel behavior analysis and policy decision making? â¢ How can cell phone data be used to enhance access to information on travel behavior characteristics necessary for effective model applications? â¢ What tools and techniques are available for collecting and analyzing cell phone data? â¢ How can travel modelers overcome practical and legal problems associated with data acquisition, and how can this acquisition process respond to privacy requirements? These questions represent only a portion of the detailed considerations required to evaluate the potential application of cell phone data in improving travel behavior modeling as input to overall transportation planning efforts. The first three chapters of NCHRP Research Report 868 set the stage for the analysis and guidelines for practitioners by adopting a practitionerâs perspective and discussing how the strengths and weaknesses of cell phone data are likely to influence planning for transpor- tation projects. Chapters 4 through 6 provide an in-depth discussion of the types of data available and procedures that can be used to apply these data to primary issues affecting travel modeling. The report describes data available; how call detail record data are analyzed to extract daily trajectories; steps involved in identifying activity types encompassing home, work, and âotherâ; how to derive trip purpose by time of day; and, finally, methods used to develop trip tables using cell phone data. Chapters 7 and 8 present a case study approach to compare the inferred trip tables extracted from the cell detail record data with trip tables from Boston, household travel surveys, and the Boston regional travel demand model. In Chapter 9, the report concludes with guidelines for practitioners, summarizing key admin- istrative, data-related, and modeling considerations about the potential uses of cell phone data and applications by planning and modeling practitioners.
1 Summary 5 Chapter 1 Roadmap to the Report 8 Chapter 2 Travel Behavior from Cell Phone Data 8 2.1 Research Objectives 9 2.2 Current Practice: Data 9 2.3 Survey Data: Strengths and Weaknesses 10 2.4 Current Practice: Models 11 2.5 Cell Phones: Sensors for Data Collection 12 2.6 Cell Data: Strengths and Weaknesses 13 2.7 Inferring Trip Ends and Activities 13 2.8 Inferring Travel Flows 15 Chapter 3 A Plannerâs View of Cell Phone Data 15 3.1 Cell Phone Data in Transportation Planning 19 3.2 Transportation Planner Needs 24 3.3 Utility of Cell Phone Data 30 3.4 Research Framework 32 3.5 Summary 33 Chapter 4 Description of Raw Data 33 4.1 Roadmap to the Chapter 33 4.2 Context: Rapid Urbanization 34 4.3 General Description of Data 37 4.4 A Closer Look at Cell Phone Data 42 4.5 Evaluation of CDR Data for This Research 55 4.6 Summary 56 Chapter 5 Extraction of Daily Trajectories 56 5.1 Roadmap to the Chapter 56 5.2 Motivation and Purpose 58 5.3 Stay Extraction Algorithms 60 5.4 Stay Extraction Results 67 5.5 Mapping Stay Locations to Zones 68 5.6 Summary 69 Chapter 6 Measuring Individual Activities: Home, Work, âOtherâ 69 6.1 Roadmap to the Chapter 69 6.2 Activity Inference 75 6.3 Validation 76 6.4 Summary C O N T E N T S
78 Chapter 7 Trips by Purpose and Time of Day 78 7.1 Roadmap to the Chapter 78 7.2 Concept of Ground Truth 80 7.3 Modeling Departure Time 81 7.4 Modeling Person-Trips 83 7.5 Time-of-Day Patterns 84 7.6 Activity Duration Patterns 85 7.7 Daily Trip-Making Patterns 87 7.8 Commuter Flows 89 7.9 Summary 90 Chapter 8 Model Comparison: OriginâDestination Trips 90 8.1 Roadmap to the Chapter 90 8.2 Data Sources and Model Definition 94 8.3 Comparisons at the Regional Level 105 8.4 Summary 110 Chapter 9 Guidelines for Practitioners 110 9.1 Roadmap to the Chapter 111 9.2 Administrative Considerations 113 9.3 Data Considerations 122 9.4 Modeling Considerations 128 9.5 Future Research Directions 132 9.6 Epilogue 133 Glossary 136 References 142 Additional Resources