Standardized Metrics for Accessibility: Establishing a Federal Policy-Relevant Knowledge Base

This project aims to accomplish for accessibility that which current mobility-based metrics do for mobility: influence decisions and establish a measurable basis for policies that help travelers reach destinations. By proposing a scheme for standardized metrics that can be used to assess accessibility, this study offers the opportunity to inject accessibility principles into transportation decision-making. Recent advances within transportation circles toward accessibility-based transportation planning can be encouraged and accelerated with standardized data collection and dissemination. Data input needed for accessibility assessment includes 1) zone-to-zone travel time and volume by travel mode; 2) population by location; and 3) indicators of destinations, such as jobs, square feet of development, or sales volumes. The first is regularly collected as part of the transportation-planning process in the course of development of regional travel-demand models. Yet despite the nominal straightforwardness of counting minutes or travelers, inconsistencies in practice abound. These enter in definitional issues pertaining to modes, trip purposes, transit headways, service areas, and so forth. They also enter in the form of fundamentally different definitions used in collecting the travel survey data that form the basis of travel-demand models. This report seeks opportunities for standardization of these data and explains findings on three principal tasks. First, it assesses the current state of standardized transportation data. By studying documentation of other programs of standardized data, including the National Transit Database (NTD) and the Highway Performance Monitoring System (HPMS), and by conducting interviews with key officials and users of these programs, the authors identify lessons about how transportation data are collected, compiled, disseminated, and archived. Second, this report documents the range of current practice with regard to the needed inputs to accessibility analysis. By conducting a review of documents and reports, and interviewing relevant users at various levels of government, the authors provide an assessment of the range of current practice with an evaluation of the characteristics and methods most appropriate for accessibility indicators. Finally, the report provides a recommended framework for standardizing the inputs to accessibility metrics. The primary goal is to eventually assemble a reliable and trustworthy data set for evaluating accessibility performance, but to do so while minimizing the burden on respondents and without suppressing the creativity and distinctiveness of initiatives at the local and regional level. The authors carried out interviews and focus groups with experts from several metropolitan planning organizations to respond to and modify the proposed approach to a standardized data scheme.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; References; Tables;
  • Pagination: 36p

Subject/Index Terms

Filing Info

  • Accession Number: 01628897
  • Record Type: Publication
  • Report/Paper Numbers: NEXTRANS Project 127UMY2.l
  • Contract Numbers: DTRT12-G-UTC05
  • Created Date: Jan 25 2017 4:42PM