Context Classification and Associated Transportation Expectations in Support of Contextual Roadway Design

Abstract

In the United States, highway functional classification has played a central role in planning and designing roadway projects. Classifications have served as a surrogate for design inputs (e.g., design speed). However, functional classification lacks the resolution needed to develop context-sensitive designs and prioritizes motor vehicles over other modes of transportation. NCHRP Report 855 introduced an expanded context classification system that supports more integrative and context-adapted roadway designs. This system was subsequently adopted in the 7th Edition of the Policy of Geometric Design for Highways and Streets (Green Book). Transitioning from functional classification to context classification as the primary basis of design entails a major shift in design practices. Context sets expectations for each setting and informs the entire project development process—from visioning to design and implementation. Based on a review of context classification systems adopted by state departments of transportation (DOTs), this paper updates the Green Book’s context classifications and introduces the concept of Transportation Expectations, which are fundamental concepts that define how users expect to move in each context. A case study focused on Lexington, Kentucky, U.S., explores these concepts and discusses how they facilitate multimodal roadway designs—the focal point of the upcoming Green Book 8th Edition.