Research | 2013

Design/Development Principles for Livable Suburban Roadways

  • Authored by:  F. Dock
  • Co-authored by:  W. Morris , C. Swenson

This research investigates the interaction between road section design and adjacent site design with the goal of pairing roadway design criteria (in terms of the maximum number of lanes and design speed) with urban design criteria (in terms of levels of activity, location of access, and relation to street). The research hypothesizes that a minimum of three arterial roadway prototypes is needed to serve travel demands and that there are three types of activity levels in suburban communities. Three types of activity centers range in intensity from low (neighborhood-scale), to medium (support smaller businesses and daily shopping, a live-work community, and give local identity to communities) to high (where job and housing densities can sustain a diverse economic base and multi-modal transportation). Three roadway prototypes and six urban design templates are developed as tools for applying the principles embedded in the design elements. These provide “a taxonomy of planning situations and a corresponding set of templates to guide design decision making for each.” (p. 11) Conclusions include:

  • The diversity of contexts means that arterials must be divided into composites of segments, designed for different speeds. Mixing of prototypes is feasible provided the segments are of sufficient length. Although they have up to ten mph difference in speed, based mostly on signal spacing, they have roughly equivalent throughput and operational capacity.
  • The spacing of signalized intersections is the defining factor as to the configuration of the planning area: “Once spacing requirements for different design speeds are established, access, location and basic block and building orientations are readily established.”
  • Although the templates are helpful, in established suburban areas, the existing context best determines how to balance activity and movement and the opportunities for phasing change in the built environment.

Other useful sources include:
1. Main Street: A Handbook for Oregon Communities, Oregon DOT, November 1999.
2. New Urbanism: Comprehensive Report & Best Practices Guide, Third Edition, New Urban News, 2003.