Multidimensional Framework for Context-Based Design of Major Urban Thoroughfares

Abstract

During the post-World War II period, conventional roadway design has been based on a functional classification system that addresses levels of vehicle movement and access to abutting properties. Traffic-carrying capacity has been the dominant consideration. In recent years, more attention has been given to other characteristics of local streets and a small number of major streets. New design standards have been developed for local (neighborhood) streets by some organizations and local agencies. At the same time, the National Environmental Policy Act has increased the importance of environmental considerations in the design of major streets and roads and highlighted the importance of minimizing impacts of roadway projects on natural resources, particularly in rural environments. However, no widely accepted design guidelines have yet been developed for urban major streets. Street design and urban design professionals share a need for a two-dimensional framework that ties together (a) roadway design criteria for an expanded palette of street types (number of lanes; target speed; pedestrian, transit, bicycle, and motor vehicle functions; other functional criteria) and (b) a set of place types that reference features of both the public right-of-way and private development fronting on the roadway and in the broader area. The conventional functional class-based design criteria do not satisfy this need. The basic structure of such a framework is discussed.