Guidebooks for Estimating Total Transit Usage Through Extrapolating Incomplete Counts
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Final Report Guidebooks for Estimating Total Transit Usage through Extrapolating Incomplete Counts September 2016 PREPARED FOR Contract DTRT-12-G-UTC22 Mod 2 Guidebooks for Estimating Total Transit Usage through Extrapolating Incomplete Counts Contract DTRT-12-G-UTC22 Mod 2 Prepared for: Maggie Schilling, NTD Program Manager Prepared by: USF Center for Urban Transportation Research Xuehao Chu, Ph.D. Final Report September 2016 Disclaimer The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Federal Transit Administration. ii Metric Conversion SYMBOL WHEN YOU KNOW MULTIPLY BY TO FIND SYMBOL LENGTH in inches 25.4 millimeters mm ft feet 0.305 meters m yd yards 0.914 meters m mi miles 1.61 kilometers km VOLUME fl oz fluid ounces 29.57 milliliters mL gal gallons 3.785 liters L ft3 cubic feet 0.028 cubic meters m3 yd3 cubic yards 0.765 cubic meters m3 NOTE: volumes greater than 1000 L shall be shown in m3 MASS oz ounces 28.35 grams g lb pounds 0.454 kilograms kg megagrams T short tons (2000 lb) 0.907 Mg (or "t") (or "metric ton") TEMPERATURE (exact degrees) 5 (F-32)/9 oF Fahrenheit Celsius oC or (F-32)/1.8 iii Technical Report Documentation 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 4. Title and Subtitle 5. Report Date Guidebooks for Estimating Total Transit Usage through Extrapolating September 2016 Incomplete Counts 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Xuehao Chu NCTR 79060-17 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) National Center for Transit Research Center for Urban Transportation Research University of South Florida 4202 East Fowler Avenue, CUT100, Tampa, FL 33620 11. Contract or Grant No. U.S. DOT DTRT-12-G-UTC22 Mod 2 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Research and Innovative Technology Administration Final Report U.S. Department of Transportation, Mail Code RDT-30 August 2013–September 2016 1200 New Jersey Ave., SE, Room E33, Washington, DC 20590 Florida Department of Transportation, Research Center 605 Suwannee Street, MS 30, Tallahassee, FL 32399 14. Sponsoring Agency Code 15. Supplementary Notes Supported by a grant from the U.S. Department of Transportation 16. Abstract This report provides guidance for transit agencies to estimate transit usage for reporting to the National Transit Database (NTD) when their counting procedure that is designed to perform full counts misses some trips. Transit usage refers to unlinked passenger trips (UPT), passenger miles traveled (PMT), and average passenger trip length (APTL) in terms of annual totals and annual average daily by schedule type for annual reporting and monthly total UPT for monthly reporting. The guidance is provided in two self-contained guidebooks for bus and rail, respectively. Bus service includes all four fixed-route bus modes defined in the NTD: motor bus (MB), commuter bus (CB), bus rapid transit (RB), and trolleybus (TB). Rail includes light rail (LR), streetcar rail (SR), and hybrid rail (YR). For both mode types, the guidance focuses on data from automatic passenger counters (APC). The guidance details a methodology for determining transit usage for each mode type through stratified extrapolation of incomplete counts rather than intentional sampling with APCs. The guidance views the total transit usage determined from the methodologies as estimates rather than 100% counts. It also views each methodology as an alternative sampling technique. The guidance identifies the conditions under which transit agencies may estimate annual total transit usage with this methodology as a pre-certified alternative sampling technique. For example, agencies must pass an equivalence test by demonstrating that their APC data are statistically equivalent to paired manual data within ±7.5% at the 95% confidence level. The guidance provides detailed steps for agencies to conduct the equivalence test in an Excel environment. When agencies meet the identified conditions and follow the guidance, they may use Appendix A in each guidebook as the document of certification by a qualified statistician for the alternative sampling technique. For the NTD program, the guidance fills a gap in current NTD guidance and will result in more accurate UPT and PMT data. For agencies, it prevents under-reporting and saves the need to hire a qualified statistician for certifying the methodology as an alternative sampling technique. 17. Key Words 18. Distribution Statement National Transit Database (NTD), automatic passenger counter, Available to the public through the National unlinked passenger trips, passenger miles traveled, sampling Technical Information Service (NTIS), 5285 Port manual, sampling plans, bus, light rail, streetcar rail Royal Road, Springfield, VA 22161, (703) 487-4650, http://www.ntis.gov, and through the NCTR website at http://www.nctr.usf.edu/ 19. Security Classification 20. Security Classification 21. No. of Pages 22. Price (of this report) (of this page) 103 Unclassified Unclassified iv Acknowledgments The project and this report greatly benefited from discussions with and insights and different views provided by Keith Gates, formerly with the Federal Transit Administration (FTA); Brian McCollom with McCollom Management Consulting; Matt Bonzek with BCG Transportation, Inc.; Andeas Rakebrandt with INIT; and Tom Kowalski with Urban Transportation Associates, Inc. This report also benefited from comments and edits by Dr. Victoria Perk, Dr. Steve Polzin, Patricia Ball, and Joel Volinski with the Center for Urban Transportation Research. Several transit agencies provided paired data collected from the same sample of trips with both automatic passenger counters and human ridecheckers. v Table of Contents Disclaimer ii Metric Conversion iii Technical Report Documentation iv Acknowledgments v Part I – Introduction I-1 Part II – Bus Guidebook II-1 Part III – Rail Guidebook III-1 vi Part I – Introduction Introduction I-1 Table of Contents – Part I 1.00 REPORT ORGANIZATION ................................................................................... 3 2.00 BACKGROUND.................................................................................................... 4 2.01 NTD Requirements ............................................................................................. 4 2.02 Traditional Sampling with Manual Ridechecks ........................................................ 5 2.03 Intentional Sampling with APCs ........................................................................... 5 2.04 APC Certification by FTA ..................................................................................... 6 3.00 THE PROBLEM OF INTENTIONAL SAMPLING WITH APCS ................................... 7 3.01 Introduction ...................................................................................................... 7 3.02 Missing Data ..................................................................................................... 7 3.02.1 Reasons for Missing Data .............................................................................. 7 3.02.2 Potential Bias from Missing Data .................................................................... 8 3.03 Systematic Error ................................................................................................ 8 3.03.1 Sources of Error ........................................................................................... 8 3.03.2 Need to Consider Systematic Error in Sampling ................................................ 9 3.04 Benefits of Using All Valid Data ............................................................................ 9 3.05 Need for an Alternative Approach to Using APC Data .............................................. 9 4.00 GUIDEBOOK METHODOLOGY ........................................................................... 11 4.01 Stratified Extrapolation ..................................................................................... 11 4.02 General Conditions ........................................................................................... 11 4.03 Suggested Segmentation .................................................................................. 11 4.04 Data Requirements .......................................................................................... 12 4.05 Nature of Methodology ..................................................................................... 12 4.06 Certification .................................................................................................... 13 4.06.1 Coverage, Operations, and Data Recovery ..................................................... 13 4.06.2 Use of All Valid APC Data ............................................................................ 13 4.06.3 Continuous Monitoring ................................................................................ 13 4.06.4 Statistical Equivalence ................................................................................ 14 4.07 Benefits .......................................................................................................... 16 5.00 COMPARISON .................................................................................................. 17 5.01 Introduction .................................................................................................... 17 5.02 Definition of Each Error Type ............................................................................