How Green is your Transit System?

by Catherine Calvert, VIA's Director of Practice + Director of Community Architecture

Sustainable building design is not exactly news. Over the past 30 years, and particularly in the past 10 years, information on how to reduce the energy and resources used in building design, construction, and operation has become increasingly available to the design industry. Building rating systems such as LEED® can assist architects, municipalities, and building owners seeking a common language and understanding about what constitutes sustainable architecture.

By contrast, architects wanting to design transit systems sustainably have few guidelines to follow. Transit systems are, by definition, not buildings. Most systems consist of a collection of infrastructure and dynamic elements – trackway, vehicles, support facilities, and stations, which are often unconditioned environments, open to the elements. The environmental footprint of a transit system goes far beyond the energy and materials expended in building these facilities. There is not much point in minimizing the amount of energy used by a transit station light bulb when the energy needed to operate a system over its 50 or 100 year life outweighs this expenditure by a factor of thousands. It is important that as designers seeking to achieve transit sustainability look beyond the buildings to the system as a whole.

And what is sustainable transit, anyway? Equally important to the facilities are the decisions made about where the system and stations are located. What kind of neighborhoods does the system serve? Does zoning around the stations support compact forms of development that don’t require a car? Is there adequate density and ridership to ensure financial sustainability for the transit system? Does urban design around the stations support safe, attractive pedestrian pathways? Are the transit stations integrated into a mix of uses that meet people’s needs and support varied activity throughout the day?

Furthermore, what aspects of transit vehicle design and operation can be optimized in terms of energy consumption and resource use? How can train design take advantage of advanced technology such as regenerative braking? How can track design use gravity to assist in deceleration as trains approach stations? How can train materials be selected for healthy indoor air quality?

Transit systems around the world are all attempting to answer these questions. A few agencies, notably New York’s MTA, Hong Kong’s MTR, and Portland’s TriMet, have made sustainability a high priority and have been pioneers in the experimental application of new technologies to transit facilities. For the past five years, the American Public Transportation Association (APTA) has held an annual conference dedicated to the discussion of Transit Sustainability, most recently in Salt Lake City in August 2009. These discussions have lead to the recognition of a need for shared knowledge and the development of a set of best practices specifically addressing the needs of the transit industry.

Out of this has grown an APTA initiative led by Tian Feng, District Architect for the Bay Area Rapid Transit agency (BART), to develop a Compendium of Sustainable Transit Practices. Developed over a period of three years as an evolving brainstorm session between key transit agency representatives and private industry advisers from all over North America, these guidelines are designed to offer best practice and case studies that will be helpful to transit agencies of all modes (bus, ferry, train, light rail) and of all scales. VIA’s Founding Principal, Alan Hart and I have been key contributors to the development of this document, participating in numerous working sessions and providing editorial research to support this effort. We strongly believe that the sharing of this type of knowledge will shorten the learning curve by transit agencies seeking to build new systems or to make existing ones more sustainable.

The first draft of the Compendium of Sustainable Transit practices can be found on the APTA website: