Operationalizing Accessibility Metrics to Support Transportation Planning and Performance Management

Recent years have seen rapid growth in the research and use of accessibility metrics in transportation planning and performance management. Accessibility metrics indicate the ease with which travelers can reach valued destinations. They combine metrics indicating the cost of travel, such as travel time or financial cost, with the potential benefits—the destinations that could be reached at a given cost. This approach allows accessibility metrics to provide a uniquely comprehensive indicator of a transportation system's ability to provide opportunities to its users. For example, an accessibility metric focused on access to jobs might indicate that residents of a particular area could reach 100,000 jobs within 15 minutes by car. Because few federal or state guidelines exist regarding the use of accessibility metrics, this recent increase in use generally represents ad hoc efforts at state and local levels to meet local planning and performance management needs. The national transportation community would benefit from an analysis of these many different ways of operationalizing accessibility. Accessibility metrics can be implemented in a wide variety of ways, each of which can be useful for different purposes or different subject domains. For example, an accessibility metric designed for use in public-facing communication regarding a new highway segment could use very different data and methods from one intended for use by professional planners to identify high-priority freight corridors. However, little organized guidance is available on the selection of accessibility metrics for particular use cases. An analysis and categorization of the existing and proposed approaches to measuring accessibility can help practitioners identify the most useful accessibility metrics for their purpose, without lengthy investigation and testing. Several tools and data sources focused on accessibility exist. Tools range from large software packages to local implementations by city staff or academic researchers and exist in both open-source and commercial forms. Data sources include university-led national data processing projects, outputs from metropolitan planning organizations (MPO) planning efforts, and comparative metropolitan analyses from advocacy groups for non-motorized transportation. Both tools and data sources vary in the exact ways that they implement accessibility measurements. Regardless of the scale, scope, or subject, these tools and data sources are typically quite robust. But the fragmented landscape provides little opportunity for understanding how they relate to one another, or which one would be most appropriate to support a particular planning or performance management goal. An analysis of existing accessibility tools and data sources can help connect potential users with the most appropriate resources, while also identifying opportunities to both streamline and expand the field. Transportation agencies are currently using accessibility metrics to support a variety of planning and performance management goals. These range from states using accessibility metrics to inform project prioritization, to MPOs setting accessibility goals in long-range plans, to counties using them to support local travel demand management programs. An investigation of these case studies can help to identify the types of applications in which accessibility metrics can have the largest impact, compile lessons learned from these implementations, and share best practices with the wider transportation community. The primary objective is to identify and analyze accessibility metrics in order to provide guidance for the broader transportation community. The research is anticipated to include: (1) synthesis of accessibility metric definitions in published research and technical reports from practice; (2) classification framework for accessibility metrics; (3) decision-making recommendations for the selection of accessibility metrics for different use cases; (4) survey of existing tools and data sources that can be used to produce accessibility metrics; (5) evaluation of existing tools and data by using them to implement accessibility evaluations based on real-world examples and data; (6) case studies that identify and document lessons learned and best practices in using accessibility metrics for transportation planning or performance management; and (7)priority areas for additional development of accessibility methods with a focus on reducing barriers to use by transportation professionals. The results of the research will be provided in a guidebook for operationalizing accessibility metrics. An implementation plan will lay out an immediately actionable set of steps to facilitate the adoption of accessibility metrics in the planning and performance management activities of at least three state departments of transportation (DOTs).  


  • English


  • Status: Proposed
  • Funding: $500000
  • Contract Numbers:

    Project 08-121

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Hartell, Ann

  • Start Date: 20180709
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01672246
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 08-121
  • Files: TRB, RiP
  • Created Date: Jun 18 2018 3:02PM