Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
NCHRP Web-Only Document 330 Accessibility Measures in Practice Alex Karner Kaylyn Levine Louis Alcorn Minyu Situ The University of Texas at Austin Austin, TX Dana Rowangould University of Vermont Burlington, VT Kyeongsu Kim Connetics Transportation Group Washington, DC Ayberk Kocatepe Connetics Transportation Group Orlando, FL Conduct of Research Report for NCHRP Project 08-121 Submitted September 2021 © 2022 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved. NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest 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 initiated 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 (FHWA), United States Department of Transportation, under Agreement No. 693JJ31950003. 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, APTA, FAA, FHWA, FTA, GHSA, or NHTSA 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. DISCLAIMER The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research. They are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; the FHWA; or the program sponsors. The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications. The Transportation Research Board, the National Academies, 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 information contained in this document was taken directly from the submission of the author(s). This material has not been edited by TRB.
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. John L. Anderson 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.nationalacademies.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 provide leadership in transportation improvements and innovation through trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. The Boardâs varied activities annually engage about 8,000 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 CRP STAFF FOR NCHRP WEB-ONLY DOCUMENT 330 Christopher J. Hedges, Director, Cooperative Research Programs Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program Sid Mohan, Associate Program Manager, Implementation and Technology Transfer, National Cooperative Highway Research Program Ann Hartell, Senior Program Officer Dajaih Bias-Johnson, Senior Program Assistant Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications Jennifer Correro, Assistant Editor NCHRP PROJECT 08-121 PANEL Field of Transportation PlanningâArea of Planning Methods & Processes Karena J. Houser, Washington State Department of Transportation, Olympia, WA (Chair) Deanna Belden, Minnesota Department of Transportation, Saint Paul, MN Evelyn A. Blumenberg, University of California, Los Angeles, Los Angeles, CA Dan Lamers, North Central Texas Council of Governments, Arlington, TX Bassey Onyile, New Jersey Department of Transportation, Trenton, NJ Elizabeth Ann Sall, UrbanLabs LLC, Seattle, WA Jason Bryan Schronce, North Carolina Department of Transportation, Raleigh, NC Monica Y Zhong, Florida Department of Transportation, Tallahassee, FL Alexis Kuklenski, FHWA Liaison Ken J. Cervenka, FTA Liaison Caroline Kieltyka, AASHTO Liaison
- iv - Table of contents List of figures ................................................................................................................................. v List of tables................................................................................................................................... v 1 Introduction and summary .................................................................................................... 1 2 Literature and practice review .............................................................................................. 4 2.1 Accessibility research ..................................................................................................... 4 2.1.1 Accessibility dimensions and data requirements ........................................................ 5 2.1.2 Specific accessibility measures ................................................................................. 11 2.2 Accessibility practice .................................................................................................... 27 2.2.1 Performance measurement, management, and accessibility .................................... 27 2.2.2 State departments of transportation.......................................................................... 29 2.2.3 Metropolitan planning organizations ....................................................................... 35 2.3 Summarizing the state of the art and practice ............................................................... 39 3 Practitioner interviews ......................................................................................................... 40 3.1 Methods and data .......................................................................................................... 40 3.1.1 Semi-structured interviews ........................................................................................ 41 3.1.2 Online survey of interviewees ................................................................................... 45 3.2 Results and discussion .................................................................................................. 46 3.2.1 High-level themes...................................................................................................... 47 3.2.2 Accessibility measure evaluation and use................................................................. 56 3.3 Conclusions ................................................................................................................... 64 4 Gaps, challenges, and limitations ........................................................................................ 66 4.1 Conceptual gaps ............................................................................................................ 67 4.1.1 Using accessibility as mobility.................................................................................. 68 4.1.2 Narrow concept of accessibility ................................................................................ 69 4.1.3 Difficulty capturing unmet travel needs .................................................................... 77 4.1.4 Limited characterization of virtual access ................................................................ 79 4.1.5 Challenges applying accessibility measures across different contexts ..................... 80 4.2 Data gaps ....................................................................................................................... 80 4.3 Implementation gaps ..................................................................................................... 81 4.3.1 Lack of use ................................................................................................................ 81 4.3.2 Limited use ................................................................................................................ 81 4.4 Conclusions ................................................................................................................... 82
- v - Appendix A: Interview protocol for practitioners ................................................................... 83 Appendix B: Interview protocol for software/data producers ............................................... 88 Appendix C: Accessibility overview for interviewees (interview slide deck) ........................ 91 Appendix D: Interview qualitative codebook ......................................................................... 101 Appendix E: Respondent survey ............................................................................................. 105 Appendix F: Survey results for all respondents ..................................................................... 110 Appendix G: Implementation of research findings and products ........................................ 115 Appendix H: References ........................................................................................................... 119 NCHRP Web-Only Document 330: Accessibility Measures in Practice is associated with NCHRP Research Report 1000: Accessibility Measures in Practice: A Guide for Transportation Agencies. Readers can read or purchase NCHRP Report 1000 at www.trb.org. List of figures Figure 1. Example accessibility index computed using proximity (Euclidian distance) as impedance. .................................................................................................................................... 13 Figure 2. Population distribution of access to convenience stores by race in the Detroit, MI metropolitan area. ......................................................................................................................... 17 Figure 3. Perspective view showing density of less-educated job seekers (top) and less-skilled job openings in total (bottom) in Boston, MA and surrounding region........................................ 18 Figure 4. Classical definition of the space-time prism and potential path area. ........................... 22 Figure 5. Individual difference comparison for a 20% reduction in travel time by mode compared between high- and low-income groups. ........................................................................................ 25 Figure 6. Summary of accessibility measure evaluation by survey respondents. ......................... 58 List of tables Table 1. Accessibility measure data and candidate sources. .......................................................... 8 Table 2. Six types of accessibility measures with simple descriptions. ........................................ 11 Table 3. Three additional measures later identified and discussed in the Guide. ......................... 12 Table 4. Proximity measures study summary. .............................................................................. 14 Table 5. Access to opportunities study summary. ........................................................................ 16
- vi - Table 6. Competitive measures study summary. .......................................................................... 19 Table 7. Trip characteristics study summary. ............................................................................... 21 Table 8. Potential path areas study summary. ............................................................................... 23 Table 9. Logsum study summary. ................................................................................................. 26 Table 10. MAP-21 national performance goal areas. ................................................................... 27 Table 11. All state DOTs using or developing accessibility measures, by the type of measure used and its description. .................................................................................................. 31 Table 12. Accessibility measures found in MPO plans. ............................................................... 37 Table 13. Organizations interviewed. ........................................................................................... 42 Table 14. Survey responses by agency type. ................................................................................ 46
