…By Planning Roads at an Ecosystem Scale and Integrating Sustainable Features

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Today, only a limited number of infrastructure projects in the United States are new roads. In fact, more than nine out of ten highway projects that require evaluation under the National Environmental Policy Act (NEPA) are classified as categorical exclusions, and thus are actions considered to involve no significant environmental impacts, based on a precedent that the environmental review of similar actions has set.[1]

The only way to ensure that critical environmental and cultural resources are protected when a new road is built is to select an alignment that avoids them. Certain circumstances require roads to be constructed in or near sensitive resources; for example, a region may need a new road to respond to changes in population and land use, to replace obsolete facilities, to provide equitable access to transportation, or to facilitate economic development. A new road may also be necessary to enhance safety and emergency preparedness. For purposes such as these, the public’s need for safe and efficient transportation solutions must be taken into account.

When a region determines that building a new road is in the best public interest, the transportation delivery process presents at least two broad types of opportunities to honor the landscape: those possible through the transportation-planning and environmental-permitting processes, and those possible through the application of certain technological, operational, and design features. Regarding the first opportunity, the transportation-planning and environmental review processes historically existed in separate spheres, but the state of the practice has changed, and the use of an “integrated planning” approach is helping transportation and environmental practitioners to examine natural resource concerns prior to formal transportation-planning activities. By exploring environmental, economic, and other societal goals during the planning process and then carrying them through project development, design, and construction, resulting road projects can better reflect the priorities of the community and relevant agencies.

When assessing infrastructure projects within a given region, integrated planning allows agencies with different missions and areas of expertise at local, state, and federal levels to collaborate. Together, they can identify critical ecological resources and mitigation opportunities and then select the most ecologically appropriate alignment. In cases where key resources cannot be avoided, the agencies can develop a list of mitigation options within the same ecosystem or watershed, while also creating a plan for infrastructure features that may lessen any negative environmental impacts of the road. Some of these features are new techniques that transportation agencies have demonstrated through recent research, while others have been available for many years but not regularly applied.

Green infrastructureIt is those features that can help roads of the present and future “look” and perform better than some roads may have in the past. For example, transportation agencies can install erosion, sediment, and run-off control measures to ensure that stormwater impacts resulting from new roads are alleviated. Transportation agencies might also implement policies or pricing strategies that reduce idling times in order to address air quality issues or to attempt to manage congestion. In other scenarios, transportation agencies can use unpaved portions of roads that are beyond the “clear zone,” or area necessary to ensure traveler safety, to sequester carbon or grow biocrops via alternative management practices for the native vegetation already present at the site of the road. When the proposed new road is located in a landscape where the new infrastructure might cause habitat fragmentation, disrupt migration patterns, or split species populations, measures such as well-designed box culverts, wildlife overpasses/underpasses, and wildlife fencing can be installed to support habitat connectivity and to help offset other negative impacts of the road. Additionally, some transportation agencies are piloting ways to put new roads to work generating power through incorporating renewable energy technologies—including solar panels, wind turbines, and geothermal devices—into roadway design. The rapidly maturing state of the practice suggests renewable energy applications within highway right-of-way can promote energy security, reduce emissions, and foster the creation of local green job markets.

All of these considerations create a series of trade-offs that a region will need to balance with its stated values when building a road is the best approach to meeting the need for a proposed project within a region. If a region decides that a road should be built, an evaluation approach should be put in place to assess the relative success of that road in honoring the landscape and achieving other goals. This mechanism should be articulated during the project planning stage to ensure that goals are not selectively met; it will serve as a reminder of the intent of the project to be environmentally sensitive, while requiring the agencies involved to measure whether decisions have ultimately accomplished what the public need warrants and the community has affirmed.

[1] U.S. Department of Transportation, Federal Highway Administration, “FHWA Projects by Class of Action” and “FHWA Projects by Funding Program Amounts,” http://environment.fhwa.dot.gov/strmlng/projectgraphs.asp

Image Credit

“Redi-Rock_ledgestone-gravity-setback-roads-EagleWest-LowLevelRoad2” by Redi-Rock International. (CC BY 2.0)

  • Carson Poe

    Carson Poe is a Transportation Industry Analyst with Volpe, The National Transportation Systems Center. His current research areas include climate change adaptation and mitigation, land-use and property management, and the National Environmental Policy Act process.

  • Julianne Schwarzer

    Julianne Schwarzer is an Environmental Protection Specialist with Volpe, The National Transportation Systems Center. Her current work focuses on environmental and ecosystem-scale planning, environmental policy, and programmatic outreach and facilitation.

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