The American Society of Landscape Architects (ASLA) has launched a new guide to transportation, with in-depth sections on how to plan and design more sustainable regional, urban, neighborhood, and street transportation systems.
Transportation infrastructure is a significant part of the landscape. The original social network, it connects us to families and friends, jobs and businesses, education and recreation, and is a vital part of the public realm. However, conventional, car-centric approaches to transportation have contributed to negative outcomes for people and the environment:
- The transportation sector is responsible for as much as 30 percent of total greenhouse gas emissions, the primary cause of climate change.
- Nearly 40 percent of American adults are now obese; and those who are most reliant on cars are most at-risk of becoming obese.
- Traffic collisions are a global public health epidemic, killing 1.25 million and injuring 50 million annually worldwide.
- Highways and interstates have been built through the middle of cities and neighborhoods, dividing communities and creating corridors of air, noise, and visual pollution. Poor, minority, and otherwise-disadvantaged communities often bear the brunt of these costs.
- In too many communities, access to jobs, services, and social networks is dependent upon ownership of a costly personal vehicle. Many residents of sprawling suburban and rural areas are trapped in “transit deserts” without viable alternatives to car ownership, limiting their access to jobs, food, and even medical care.
- Infrastructure has been built in vulnerable areas using design approaches that do not take the effects of climate change into account, increasing risk of failure and stranding evacuees in increasingly-frequent extreme weather events.
- Transportation infrastructure can be a gateway for invasive plants that crowd out native plant communities and damage sensitive ecosystems.
- Highways contribute to habitat degradation and fragmentation, leading to dwindling wildlife populations and reduced biodiversity.
- Stormwater runoff from streets and other paved surfaces is laden with pollutants from cars, leading to downstream pollution and degraded water quality in streams, rivers, lakes, and estuaries.
These outcomes are not inevitable, however. Sustainable transportation is:
Low-emission: Sustainable transportation systems don’t contribute to climate change; instead, they encourage low-emission modes of transportation such as mass transit, biking, or walking. Sustainable land use practices such as transit oriented development facilitate multi-modal systems where residents can easily walk or bike to meet basic daily needs. Landscape architects plan regions, cities, and neighborhoods and design streets that support widespread adoption of low-emission transportation options.
Active: A lifestyle organized around human-powered transportation choices such as walking and biking is healthy. A 2016 report found that walkable, transit-oriented communities increased physical fitness and mental health. Residents of such communities were also more likely to meet or exceed daily physical activity recommendations. Landscape architects encourage active transportation by designing safe, pleasant routes for walking and biking.
Safe: The World Resources Institute estimates that more than 1 million lives could be saved annually from wider adoption of traffic calming measures such as lower speed limits, reduced lane widths, and protected medians. Landscape architects design for safety and help cities eliminate serious injuries and fatalities on roadways.
Equitable: Access to such healthy, sustainable transportation options should be viewed as a right. All residents—regardless of their income, race, age, disability, religion or national origin—should have access to affordable, safe, accessible, multi-modal transportation options that allow them to fully participate in the community. Landscape architects facilitate community-driven planning, policy making, and design that includes all members of the community, especially those most affected by poverty, communities of color, and historically-marginalized communities.
Resilient: Extreme weather events can easily shut down transportation networks. Multi-modal transportation systems are resilient to the uncertainties posed by climate change, such as rising temperatures, more frequent and intense storms, and sea level rise. Landscape architects design systems with multiple, interconnected transportation options that create redundancy and flexibility, qualities that help communities evacuate and rebuild quickly in the face of natural disasters.
Ecological: A sustainable transportation network is ecological, working with natural systems to capture and filter stormwater, reduce flooding, support pollinator species, strengthen biodiversity, and protect wildlife populations. With green infrastructure, wildlife crossings, pollinator highways, and environmentally-sensitive roadway alignment, design, and construction, landscape architects integrate nature into our transportation networks, reaping the benefits of ecosystem services while minimizing conflict between humans and wildlife.
Beautiful: As a major component of our landscape and public realm, transportation infrastructure should be beautiful, inviting, and memorable. Thoughtful design creates durable, lasting spaces that forge community identity, equity, and ownership. Landscape architects ensure that transportation infrastructure contributes to the aesthetic value of the built environment.
A special thanks to our expert advisory panel for their guidance: Diane Jones Allen, D. Eng, ASLA, PLA, associate professor and program director of landscape architecture, University of Texas, Arlington, and principal, DesignJones LLC; Jean Senechal Biggs, ASLA, senior project manager, DKS Associates; and Robert Loftis, PLA, ASLA, associate landscape architect, MRWM Landscape Architects.
This guide is a living resource, so we invite you to submit research, studies, articles, and projects you’d like to see included.