NCHRP Research Report 855: An Expanded Functional Classification System for Highways and Streets served as a key reference informing the seventh edition of AASHTO’s A Policy on Geometric Design of Highways and Streets (Green Book). The new Green Book introduces a change in guidance for state transportation officials by introducing a broader set of land use context classifications (i.e., rural, rural town, suburban, urban, and urban core). These context classifications provide a mechanism for better targeting design solutions to specific contexts while providing needed flexibility to address planning and design needs.
The AASHTO Committee on Design has begun planning for the eighth edition of the Green Book and envisions a major restructuring. This includes organizing design guidance by the context classifications listed in the seventh edition with the addition of a context classification, "Industrial, Warehouse, or Port Roads." NCHRP Project 15-77, "Aligning Geometric Design with Roadway Context" will be drafting these chapters.
Many state, regional, and local transportation and planning agencies are interested in applying the new context classifications in their jurisdictions. The existing research and guidance, however, does not point to specific methodologies or parameters for implementing these context classifications. Research was needed to help agencies proceed efficiently and consistently.
The objective of this research was to develop practical guidance to assist state, regional, and local planners in identifying the appropriate context classification(s) for an area or a transportation project. Critical questions were (1) what are the context(s), (2) how will those context(s) change (spatially and temporally), and (3) what are the implications for the various travel modes.
The final report documents the research objectives, methodology, findings, conclusions, and recommendations, including:
- A summary of approaches that state, regional, and local transportation agencies have used to determine the context classification of a project, included form-based codes.
- Inventory of data sources and tools that could be applied to context classification decisions.
- A final report that documents the entire research effort with an executive summary that outlines the research results.
- Short info-graphic briefing(s) for policy- and decision-makers on the key research findings.
This project is complete and has been published as NCHRP Research Report 1022, "Context Classification Application: A Guide." The final report is available on the NCHRP Research Report 1022 blurb page.