Transportation corridors and facilities are major components of the nation’s landscape and public realm. Integrating comprehensive transportation planning with natural systems analysis and land use planning is essential for creating livable communities in sustainable environments.
The alignment, scale, and character of our thoroughfares play an integral role in determining urban form, development patterns, and a sense of place. Streets and highways should enhance interconnected transportation options, particularly for pedestrians, bicyclists, transit riders, and people with disabilities. All multi-modal transportation systems should be safe, efficient, convenient, and beautiful.
Sustainable Transportation Planning
Sustainable communities have well-connected, easily accessible transportation networks that provide attractive, safe, comfortable, and cost-effective access; improve mobility; and support economic vitality as well as environmental quality. Sustainable transportation planning should be a component of regional and local land use planning, matching infrastructure capacity with current and proposed land uses.
Well-managed transportation corridors should preserve the inherent natural and cultural characteristics, while balancing transportation, community, and environmental considerations. As members of interdisciplinary teams, landscape architects help locate transportation corridors and facilities, fit roadways to the terrain, reduce cuts and fills, and enhance travel experiences.
"Cities for Cycling: Creating Bike-Friendly Streets," The Dirt blog
"How to Design a Bicycle City," The Dirt blog
"E.P.A. Smart Growth Awards Applaud Projects That Use Collaborative Approaches and Reclaim Public Space," The Dirt blog
Interview with Jeff Speck, Co-author of The Smart Growth Manual, ASLA
Inteview with Joyce Lee, Director, Active Design Program, NYC Government, ASLA
Interview with Peter Calthorpe, Author of Urbanism in the Age of Climate Change, ASLA
"Liveability to the Rescue," The Dirt blog
"Living Near Public Transportation May Lengthen Your Life," The Dirt blog
"Streetcars Are Central to Sustainable Communities," The Dirt blog
"Sustainable Roundabout Manages Stormwater and Traffic," The Dirt blog
"The Explosive Growth of Bus Rapid Transit," The Dirt blog
"Recommendations for Improving Health Through Transportation Policy," Centers for Disease Control and Prevention
"Evaluating Public Transportation Health Benefits," Victoria Transport Policy Institute, June 2010
"Active Transportation for America: The Case for Increased Federal Investment in Bicycling and Walking," Rails to Trails Conservancy
"Capturing the Value of Transit," Center for Transit-Oriented Development, November 2008
“Cost-Effective GHG Reductions through Smart Growth and Improved Transportation Choices: An Economic Case for Strategic Investment of Cap-and-Trade Revenues,” Steve Winkelman, Allison Bishins, and Chuck Kooshian, Center for Clear Air Policy Transportation and Climate Change Program, June 2009
“Environmental Assessment of Passenger Transportation Should Include Infrastructure and Supply Chains,” Mikhail V. Chester and Arpad Horvath, University of California, Berkeley, June 2009
“Making Transportation Sustainable: Insights from Germany,” Ralph Buehler, John Pucher, Uwe Kunert, Metropolitan Policy Program, Brookings Institution, April 2009
“Sustainable Transport that Works: Lessons from Germany,” Eco-Logica, April 2009
"Innovative State Transportation Funding and Financing: Policy Options for States," NGA Center for Best Practices, January, 2009
"Fostering Equitable and Sustainable Transit-Oriented Development," Living Cities, 2009
"A Sustainable Future for Transport: Towards an Integrated, Technology-Led and User Friendly System," Commission of the European Communities, 2009
“The Road… Less Traveled: An Analysis of Vehicle Miles Traveled Trends in the U.S.,” Robert Puentes and Adie Tomer, Metropolitan Policy Program, Brookings Institution, December 2008
"Transit and Development: Increasing Transit’s Share of the Commute Trip," Reconnecting America and the Center for Transit-Oriented Development, August, 2008
“Sustainable Transportation Planning: Estimating the Ecological Footprint of Vehicle Travel in Future Years,” Guangqing Chi and Brian Stone, Jr., Journal for Urban Planning and Development, 2005
Transit Revitalization Investment District (TRID) Master Plan, Philadelphia, Pennsylvania (Interface Studio)
Urban Corridor Planning, Houston, Texas (The Planning Partnership)
Infrastructure for All, ASLA
Siting Sustainable Transportation Infrastructure
Collectively, transportation support facilities greatly affect a community’s character and quality of life, and must be carefully designed and sited. Transportation corridors and facilities, including those above and below ground should be sited to minimize impacts on adjacent land uses. Transit and bus stations, airports, rail depots, and ports should be carefully integrated into the community and serve as inter-modal facilities. Parking facilities should be designed and managed to minimize visual and physical impacts and the consumption of land, while maintaining safety.
"Increasing Public Transport Use with Smart Campaigns," The Dirt blog
Building Community Through Transportation, Project for Public Spaces
Whole Building Design Guide, National Institute of Building Sciences
Penn Connects: A Vision of the Future, Sasaki Associates
Designing Safe, Visually Appealing Transportation Infrastructure
Special care needs to be given to the preservation of historic roads and parkways, transit and rail facilities so these facilities meet current needs while respecting their character-defining elements. Some elongated “parks” may exclude billboards and freight use, limit access points and speeds, and provide overlooks and recreational facilities. Special land use procedures such as scenic easements should be considered for corridors along scenic byways to preserve their visual quality and character. The visual impacts of all transportation corridors and facilities can be improved by framing views and screening eyesores, developing appropriate signage and managing vegetation. In some settings, native plants are used to provide a sense of place and to reduce potential for invasive species establishment along linear landscapes and edges created by transportation corridors.
"Bus Shelter in Philly Gets a Mini-Green Roof," The Dirt blog
"Creating Safe, Low-Impact Access to the Waves," The Dirt blog
"In Queens, Broken Concrete Keeps Pedestrians Safe," The Dirt blog
“Safety Impacts of the Emerging Display Technology for Outdoor Advertising Signs,” Jerry Wachtel, April, 2009
“Sustainable Landscape Construction: A Guide to Green Building Outdoors,” J. William Thompson and Kim Sorvig, Island Press, 2007
Sustainable Transportation and Biodiversity
Transportation facilities should also be sited to protect wildlife corridors and avoid fragmentation of wildlife habitat. Where habitat impacts cannot be avoided, innovative techniques such as wildlife over- and underpasses should be considered.
"Better Crossing Design Can Reduce Collisions Between Wildlife and People," The Dirt blog
Interview with Caroline Fraser, Author of Rewilding the World: Dispatches from the Conservation Revolution, ASLA
Interview with Kristina Hill, Ph.D., Affiliate ASLA
Interview with Lyanda Lynn Haupt, Author of Crow Planet: Essential Wisdom from the Urban Wilderness, ASLA
Interview with Nina-Marie Lister, Affiliate ASLA, on Ecological Urbanism, ASLA
Interview with Neil Chambers, Author of Urban Green: Architecture for the Future, ASLA
"Legacy of the Cold War: Germany's Gree Belt," The Dirt blog
“Biodiversity Planning and Design,” Elizabeth Leduc, Mary York, and Jack Ahern. Island Press, 2009
“Resilient Cities: Responding to Peak Oil and Climate Change,” Peter Newman, Timothy Beatley and Heather Boyer, Island Press, 2009
ARC Design Competition
Sustainable Transportation and Stormwater: Green Streets
Green infrastructure can be incorporated into urban and rural transportation networks by respecting the existing hydrological and ecological functions of the land. Through the use of permeable pavements, vegetated bioswales, and bioretention devices, green streets reduce flooding and water pollution by absorbing and filtering stormwater. In Edmonston, Maryland, new bioretention systems on the side of the 2/3 mile street now capture 90 percent of the first 1.33 inches of water on-site, beating Maryland’s own standard of 50 percent of the first inch of water. Vegetation also increases biodiversity and helps reduce air pollution by collecting particulate matter on leaves.
Green, complete streets create a diversity of transportation options, balancing a history of automobile-centric street design in favor of opportunities for cyclists and pedestrians to safely and healthfully move through communities. Bicycle lanes should be designed with a vegetated buffer to protect bicyclists from cars. Pedestrian safety is increased by using traffic-calming techniques, such as reducing the width of vehicle lanes and creating green infrastructure bump-outs from the sidewalks. Wider sidewalks are compliant with the Americans with Disabilities Act (ADA) and create opportunities for pedestrian interaction and a more dynamic and robust public street life. These green streets are also much healthier. According to a study from the Harvard School of Public Health, cyclists on a green bike path separated from vehicular traffic saw the least exposure to pollution from vehicles, an effect increased both by distance from cars and the green buffers. Complete streets enable people to walk more easily, too, improving mood and general health.
Street trees should be planted with plenty of room for roots to expand to keep them strong and healthy. When possible, structural additions such as silva cells should be used around the roots to displace load impacts from the sidewalk above. Energy-efficient lighting should be placed below the tree canopy to provide
better visibility and safety at night. Interpretive signs at key
locations also helps educate passersby about these innovations.
Building green streets creates green jobs and contributes to greater walkability in communities. New construction should incorporate as many green street features as possible. Existing infrastructure can be converted into green streets.
Green Streets, Green Jobs, Green Towns, Chesapeake Bay Trust
Green Streets Initiative
Institute for Sustainable Infrastructure
Low Impact Development Center
Project for Public Spaces – Streets and Transit
Smart Growth America
"Let's Make Sticky Streets for People!" Planetizen, 6/17/2014
Envision™ Sustainable Infrastructure Rating System, Harvard University Graduate School of Design and the Institute for Sustainable Infrastructure
“Safe and Healthy Routes for Urban Bikers.” The Dirt, 7/8/2014
Retrofit Challenges, Water Environment Research Foundation (WERF)
“Green Streets Cut Pollution More Than Previously Thought.” The Dirt, 8/15/2012
“What Makes a Street Green?” The Dirt, 4/11/2012
“Making the Case for Sustainable Streets.” The Dirt, 9/21/2011
"Green Streets for All." The Dirt, 7/8/2010
“Complete Streets: Streets as Public Space.” The Dirt, 9/11/2010
Interview with Sandra James, International ASLA, City and Greenways Planner, City of Vancouver, ASLA
Rethinking the Street Space: Why Street Design Matters, Planetizen
"Vancouver's Green Streets," The Dirt, 9/19/2009
Green Streets Program, Bureau of Environmental Services, City of Portland Government
NYC Street Design Manual, Department of Transportation, NYC Government
Green Streets Program, Philadelphia Water Department
“Street Design: Part 2 - Sustainable Streets,” U.S. Dept. of Transportation Federal Highway Administration
"Sustainable Urban Site Design Manual," NYC Department of Design and Construction Office, June 2008
Bioswales/Vegetated Swales, Florida Field Guide to Low Impact Development, 2008
"High Performance Infrastructure Guidelines," Department of Transportation, NYC Government, 2005
“Cyclists breathe easier on their own paths.” Harvard School of Public Health, 2014.
“Green plants reduce city street pollution up to eight times more than previously believed,” American Chemical Society, 2012
“Effectiveness of Green Infrastructure for Improvement of Air Quality in Urban Street Canyons,” Environmental Science and Technology, 2012
“Performance of engineered soil and trees in a parking lot bioswales," Urban Water Journal, 2011
“Streetscape biodiversity and the role of bioretention swales in an Australian urban environment,” Landscape and Urban Planning, 2011
Role of the Landscape Architect
Landscape architects plan new communities and revamp existing ones to offer dense, easily navigable grids of complete, green streets. They also work with planners and engineers to plan, design, and build new complete, green streets.
City of Greensburg Main Street Streetscape, Greensburg, KS (BNIM)
Green Alleys, City of Chicago,
Green Street, City of Edmonston, Maryland
NE Siskiyou Green Street, Portland, Oregon, Kevin Robert Perry
Portland Mall Revitalization, Portland, OR (ZGF Architects LLP)
Streets Edge Alternatives (SEA Streets) Project, City of Seattle
SW Montgomery Green Street: Connecting the West Hills to the Willamette River, Portland, OR (Nevue Ngan Associates)
Combating the Urban Heat Island Effect from transportation infrastructureAppropriate vegetation can reduce air, light, and noise pollution, avoid soil erosion, and provide shade to mitigate the effects of the urban heat island.
“Correlating Transportation, Energy Efficiency, and Urban Heat Island Mitigation,” David Leopold, Streetscape and Sustainable Design, City of Chicago
“Cool Pavements, Reducing Urban Heat Islands: Compendium of Strategies,” Environmental Protection Agency
"Europe’s Grass-lined Green Railways," Inhabitat.com, 2009