Sustainable Transportation Networks

Media from the 2008 Transportation Summit is now available. To access media from the summit, please link to: www.cnu.org/presentations. At the presentations page, choose "Transportation Summit 2008" as the event and click submit. The most updated list of presentations will then appear. Be sure to check the presentation library as additional media will be available.
Please consult the updated Summit Agenda.

The following papers (You can click on the links to open pdf files of the papers.) were used as discussion starters for discourse in breakout groups at the Summit in order to define CNU's "platform" for sustainable transportation networks.

Since 2002 participants in CNU’s Sustainable Transportation Network Initiative have developed approaches to integrate transportation and New Urbanist goals. Important milestones include the outline of Modern Network Design drawn from work at the 2003 Transportation Summit in Nashville, Context Sensitive Solutions produced in collaboration with the Institute of Transportation Engineers, and subsequent discussions in 2006 in Boulder, and at this year’s Congress in Austin.

Examining transportation systems as networks has proven to be a significant, and welcome departure from traditional views on transportation planning. With this new view has come the challenge of reworking many assumptions about what transportation systems ought to provide. It will ultimately require reconsideration of many existing planning practices.

Participants in this year’s Transportation Summit worked to advance this effort in breakout sessions on various aspects of sustainable transportation networks. While participants gravitated to particular topics, their interrelated nature made a review of all the following materials valuable.

Introduction - The CNU’s ongoing work on transportation focuses on the relationship between traffic and land use, the inclusion of all modes of transportation, and significantly, a re-orientation of the hierarchies by which transportation systems are defined, planned and built. A further articulation of these ideas will allow urban designers, transportation planners and others to move beyond the conventional program of urban development dominated by the mixed advantages and disadvantages of automobile transportation.

Defining and Measuring the Sustainable Transportation Network - What do we mean by network? What are its principles? What are the key characteristics of a sustainable - as compared to a conventional - network? What are the bet ways for us to measure the performance of sustainable transportation networks across all modes in terms of traditional and alternative measures? What contributions can a sustainable transportation network make to the issue of climate change and the energy crisis? What are the expectations, metrics, and possible research that are desired?

Network and Place - Transportation planners in some regions, including the Portland Metro area and Arbemarle County, Virginia have begun to describe transportation systems using transects or context zones (i.e., rural, suburban, neighborhood, city center, urban core, special district). This approach encourages the integration of land use and transportation, allowing thoroughfares to be designed based on current and projected activity within an area, not just traffic volume. It also provides a much-needed framework for addressing walkability. Summit participants are encouraged to consider how this new method may be refined and applied to large-scale systems.

Network and Modes - Improvement of transportation networks across modes demands the use of analytical tools that accurately describe modal activity, and indicate opportunities for mode service expansion. Transit service, while typically occurring along corridors, should take into account the corridor type, as well as addressing activity intensity, interconnections within the transit system, and opportunities for transfer to other transportation modes. Meanwhile, bicycle and pedestrian components of the network should emphasize safety, variety of route choice, and mode transfer points.

Implementation Policies and Barriers - Existing planning and funding practices commit resources to existing corridors, and generally assume the continued use of corridors as automotive conduits. A variety of barriers impede the implementation of a more balanced network approach, while new methods for planning and modeling finely connected transportation systems deserve further articulation. To take hold, this re-orientation of transportation policy will need to be publicized and marketed to the various groups engaged in transportation infrastructure investment.

Emergency Response & Street Design - Since 2007, CNU has worked with the US Environmental Protection agency and emergency responders to address concerns about response time on compact streets advocated by new urbanists. Perhaps not surprisingly, narrow streets have been found to be safer than wide streets, one factor helping to encourage the revision of national and state fire codes to accommodate streets narrower than the 36’ currently required in many places.

Thanks to everyone for their participation in Charlotte. We look forward to advancing discourse at next year's Summit in Portland.

Previously Published Reading Materials

1. Summaries of Network working sessions held during CNU XVI: The Metrics of Networks, The Network and Transit, Defining the Network, Implementation Barriers and Networks and Sustainability.

2. The summary of our Network/Implementation group discussion (Word) from the 2006 CNU Transportation Summit in Boulder.

3. PowerPoint on Connectivity (PPT, 6.7 MB), kindly provided by Scott McCarey of Charlier Associates, presented at the Colorado APA conference.

4. Summary of Previous CNU Network Group (PDF 1.4 MB) (convened at the Nashville CNU Transportation Summit). This document remains (in parts) unfinished but was submitted for comment to CNU (which is where the effort ended at the time). It represents an excellent starting point for a continuing discussion of the subject.