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National Inventory of Specialty Lanes and Highways: Technical Report

Chapter 2. Information-Gathering Approach

The project team conducted a comprehensive national review of specialty lanes and highways across the United States. The project team made note of the many variations of project naming conventions, such as the term managed/HOV lanes in the Dallas/Fort Worth region, diamond lanes in Houston, and the express lanes where carpools receive a toll discount. Non-toll parkways and arterials with weekday commute-reverse lanes were not part of the research scan.

The research scan used three different methods for gathering and compiling information:

  • In-depth review of the existing literature, project websites, and available databases.
  • Surveys of FHWA representatives, state DOTs, tolling authorities, and project sponsors.
  • Conference calls with select individuals and entities who helped in explaining their system through other formats.

Review of Existing Literature and Project Websites

The project team completed a research scan focused on defining the schema for use in categorizing the inventory. The literature review focused on a set of key reference documents, pulling data and information about projects for inclusion in the inventory. The key references reviewed included the following documents:

  • FHWA HOV/MUL Pooled Fund Study Excel File of HOV and Managed Lanes (2007).
  • FHWA Priced Managed Lane Guide (2012).
  • FHWA Impact of Exempt Vehicles on Managed Lanes (2014).
  • FHWA ATDM Project Deployment Database (2016).
  • TRB Managed Lane Committee Inventory (2017).
  • FHWA Toll Facilities in the United States (2018).
  • Texas A&M Transportation Institute Inventory of Priced Managed Lanes (2018).
  • FHWA Center for Innovative Finance Support P3 Project Profiles and Maps.

An internal FHWA aggregation titled List of Specialty Lanes in the U.S. began circa 2013 as an informal tracking of these many facilities; and provided the genesis of information to develop the specialty lane inventory. Tables and appendices from the listed references provided additional information to improve the base inventory information. Researchers then scanned various State, regional, and local websites to complete inventory attributes for each facility. The appendix provides a full list of the websites used.

Use of Expert Review Panel

To assist in the development of inventory attributes and collection, the project team developed a list of individuals who could serve on an expert review panel (ERP). The purpose of the ERP was to comment on and review the definitions, classifications, and attributes of various specialty lanes and highways. Additionally, the ERP reviewed major deliverables and visualizations, with an emphasis on evaluating the suitability and practical usefulness for outside audiences. Members of the ERP represented the following organizations:

  • International Bridge Tunnel and Turnpike Association (IBTTA).
  • North Central Texas Council of Governments.
  • Georgia Department of Transportation (GDOT).
  • State of Colorado, E-470 Public Highway Authority.
  • Transportation Research Board (TRB) Standing Committee on Managed Lanes Committee.
  • California Department of Transportation (Caltrans).
  • Federal Highway Administration (FHWA).
  • Florida Department of Transportation (FDOT).

Data Inventory Schema Development

During January 2019, the project team hosted a web-based conference call with the ERP to gather feedback on the inclusion of data elements for the National Inventory of Specialty Lanes and Highways. The panel provided feedback on a list of roughly 50 data elements with attention to whether that element must be included, may be included, or need not be included in the final inventory. Generally, the panel members provided similar feedback on the inclusion of data elements related to physical characteristics (e.g., lane-miles and number of lanes) and exclusion of specific toll rate and performance data (e.g., maximum toll rates). The panel believed the inclusion of toll rate information would cause the inventory to quickly lose relevance over time because trends related to toll changes can often change. Overall, the ERP suggested a reduction in the number of data elements for the inventory and recommended a focused effort on gathering high-priority information about key project attributes. Chapter 3 provides the final version of these data definitions.

Data Validation

After the project team compiled an inventory from existing literature, the project team contacted FHWA representatives, State DOT personnel, and other stakeholders to verify the compiled inventory of specialty lane and highway facilities by State. Agency representatives provided valuable insight, offered edits, and verified facility attributes. In total, representatives from all 50 States and the District of Columbia and Puerto Rico were contacted. A total of 45 entities responded with edits or affirmations out of all 50 States, the District of Columbia, and Puerto Rico (a response rate of about 87 percent). The remaining five or so states had little to no facilities, and could be easily reviewed by the project team. The project team updated the inventory based on suggestions and edits from this outreach effort. Throughout the data validation process, the project team made an extra effort to validate reported data from the agency representatives, using institutional knowledge when needed.