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Public Roads - November/December 2011

November/December 2011
Issue No:
Vol. 75 No. 3
Publication Number:
Table of Contents

In Pursuit of Sustainable Highways

by Benjamin W. Cotton

A new self-evaluation tool, an expert working group, and research on new paving systems are among the ways FHWA is helping transportation agencies meet present and future needs.

Hot in-place recycling, as shown here, rehabilitates pavements with minimal use of new materials. Recycling and reuse of materials are among the 30 Project Development criteria represented in INVEST, FHWA's new sustainability self-evaluation tool.

In the transportation industry, projects and systems serve many different and sometimes competing objectives, including safety, mobility, environmental protection, livability, and asset management. A sustainable approach seeks to meet all of these needs while hitting economic targets for cost-effectiveness throughout a highway's life cycle.

For the Federal Highway Administration (FHWA), a sustainable approach to highways means helping decisionmakers make balanced choices among environmental, economic, and social values—the triple bottom line of sustainability—that will benefit current and future road users. A sustainable approach looks at access (not just mobility), movement of people and goods (not just vehicles), and provision of transportation choices, such as safe and comfortable routes for walking, bicycling, and transit. Sustainability encapsulates a diversity of concepts as well, including efficient use of funding, incentives for construction quality, regional air quality, climate change considerations, livability, and environmental management systems.

Over the years, highway agencies have been adopting sustainable methods to comply with State or local regulations, to address environmental issues related to specific projects, or to meet other project or agency goals. Until recently, however, national-level guidance on just what it means to be a sustainable highway did not exist. That's why FHWA set its sights on developing the Infrastructure Voluntary Evaluation Sustainability Tool (INVEST), a Web-based collection of best practices that enables transportation practitioners to evaluate the sustainability of their projects.

Development and pilot testing of the new self-evaluation tool, establishment of a sustainability working group, and creation of a Sustainable Pavements Program are among the efforts underway at FHWA to help State and local agencies document and improve the sustainability of the Nation's roadways.

Developing a Self-Evaluation Tool

How do you know if your highway project is sustainable? To help highway agencies answer this question, in 2010 FHWA began developing INVEST. Using this Web-based self-evaluation tool, transportation practitioners will be able to integrate sustainability best practices into their roadway projects and evaluate their projects against existing sustainability best practices, known as criteria in the tool's evaluation system.

Use of INVEST is voluntary and is not intended to rank highway projects or compare transportation agencies against each other. Rather, FHWA designed the tool to educate and offer support to those agencies interested in incorporating sustainable practices into their highway programs. Although measuring sustainability is an imperfect science, the tool can help agencies do the following:

  • Learn more about sustainability practices in roadway planning, design, and construction.
  • Track and assess progress against these practices.
  • Make informed decisions about sustainability tradeoffs.
  • Communicate highway sustainability benefits and goals to stakeholders.

The tool is structured around a scoring function that enables State, regional, and local transportation agencies to accumulate points based on sustainability efforts at a programmatic level or as incorporated into a specific transportation project. Criteria are grouped into three modules—System Planning, Project Development, and Operations and Maintenance—with the recognition that sustainability objectives evolve throughout the life of a highway. System Planning criteria focus on an agency's efforts to incorporate sustainability into the highway planning process; Project Development criteria target specific highway construction projects; and Operations and Maintenance criteria identify sustainable measures that an agency can incorporate throughout a highway's serviceable life. Each category is scored independently from the others, allowing agencies to apply the tool in ways that are relevant to current policies, programs, and projects, while shelving those components of the tool that are not immediately applicable.

The Project Development module, for example, can be applied in its basic format, which includes 20 criteria, or in its extended format, consisting of 30 criteria. The basic scorecard is applicable to projects such as small reconstruction jobs and bridge replacements that do not expand the capacity of the roadway; preservation projects for extending the service life of existing facilities and for safety enhancements; and initiatives to restore pavement structure, ride quality, and spot safety. The extended scorecard is intended for larger projects with more significant changes and investments and, therefore, more opportunities to apply sustainable solutions. These include construction projects for a new roadway facility or structure, as well as major reconstruction projects that add travel lanes to an existing roadway or bridge. The tool automatically tallies the score and assigns the project a bronze-, silver-, gold- or platinum-level status based on the project's sustainability characteristics.

FHWA developed INVEST with substantial input from State departments of transportation (DOTs) and industry trade organizations, including the American Association of State Highway and Transportation Officials (AASHTO). Already, FHWA has presented INVEST at numerous conferences and seminars, and the project team has held multiple webinars to demonstrate the tool's functionality and how it can benefit decisionmaking and project outcomes.

"The feedback received from AASHTO and other stakeholders was instrumental in helping us clarify our intentions, focus the tool, and simplify the criteria and scoring process," says FHWA Associate Administrator for Planning, Environment, and Realty Gloria Shepherd.

GreenLITES: NYSDOT's Sustainability Rating Program

The New York State Department of Transportation (NYSDOT) created its own metrics-based, self-certification tool to raise awareness of sustainability practices already at work within the department and to expand the use of these and other emerging methods. Known as Green Leadership in Transportation Environ-mental Sustainability (GreenLITES), the tool helps the department evaluate its sustainability performance, identify effective internal practices and share them with the public, and discover new ways to improve sustainability.

NYSDOT is implementing GreenLITES in stages. The first phase was the launch of project design certification in 2008 for individual transportation projects. The next phase was operations certification in 2009 for sustainable practices in maintaining existing infrastructure and maintenance facilities.

The tool's project design module incorporates more than 175 sustainable practices, such as installing wildlife crossings and stormwater management ponds. The maintenance and operations module includes 95 green items, such as use of clean energy vehicles and context sensitive bridge repair.

GreenLITES certifies project designs in five categories:

  1. Sustainable sites—credits designs that promote a project's overall setting, such as context sensitive solutions or measures that protect, enhance, or restore ecological habitat.
  2. Water quality—credits designs that treat stormwater and reduce runoff.
  3. Materials and resources—credits designs that incorporate recycled and local materials, reuse resources, and minimize hazardous materials.
  4. Energy and atmosphere—credits designs that reduce petroleum and electricity consumption, improve traffic flow, incorporate nonmotorized transportation, or make air quality improvements.
  5. Innovation/unlisted—credits designs that promote or incorporate innovative practices in transportation and environmental sustainability.

    The tool awards points to projects based on their contributions to these categories. NYSDOT uses projects' cumulative scores to assign them to one of four GreenLITES ratings:
    • Certified—the design incorporates some sustainable elements.
    • Silver—the design incorporates sustainable elements, with several having a high level of impact or having advanced the state of the practice.
    • Gold—the design incorporates sustainable elements, with a substantial number having a high level of impact, or having advanced the state of the practice.
    • Evergreen—the design incorporates a wide variety of sustainable elements that have a very high level of impact and advance the transportation state of the practice.
Artist's rendering. This illustration shows an aerial view of a suburban intersection of Route 347 in Long Island, NY. Sustainability features transit facilities, landscaping with native vegetation, improved stormwater management, and state-of-the- art bicycle and pedestrian facilities.
This artist's rendering shows one vision for applying sustainability practices to Route 347 in Long Island, NY. Sustainability features include transit facilities, landscaping with native vegetation, improved stormwater management, and state-of-the-art bicycle and pedestrian facilities.

"Incorporating sustainability into our design and operations practices is a new way of doing business for the State department of transportation," says NYSDOT Commissioner Joan McDonald. "We are excited to be a national leader for sustainability in transportation. To date, we have evaluated more than 465 projects, and our annual awards ceremony gives the department an opportunity to recognize the maintenance and capital construction projects that best incorporate environmental sensitivity in our State's transportation system."

For more information, visit

Screenshot from FHWA's "INVEST" Web site.

Pilot Testing the Tool

FHWA released the pilot version of INVEST in three stages, available online at The Project Development module was released in April 2011, the Operations & Maintenance module in July 2011, and the Systems Planning module in September 2011. The pilot version will be active throughout 2011 with several State, regional, and local agencies testing the tool's application on their projects and programs. FHWA emphasized the importance of testing the tool's versatility on projects ranging from bridge construction and intersection improvement to highway expansion and pavement restoration.

"FHWA is excited about our progress with the pilot test version of INVEST," says FHWA Executive Director Jeffrey Paniati. "[The pilot] is a great opportunity to test the tool on real-world highway projects and refine the scoring system based on the results. We look forward to making our findings available to our partners and stakeholders once the pilot test phase of the project is complete."

Sustainability Working Group at FHWA

In addition to developing the self-evaluation tool, in the summer of 2010, FHWA convened a sustainability working group to build capacity and encourage communication and coordination on sustainability concepts and practices within the agency. The group consists of engineers, scientists, planners, and economists with expertise in planning, design, construction, pavement, stormwater management, natural resources, and livability. It meets regularly to coordinate activities, foster increased application of sustainability principles, and provide guidance to FHWA on developing best practices and establishing standardized sustainability measures.

As with many initiatives at the national level, one of the biggest challenges facing FHWA's sustainable highways program is developing a system of best practices that is applicable to transportation agencies across the country. Given vast variations in climates, habitats, geological characteristics, and availability of construction materials throughout the United States, certain sustainable practices may be valuable to some highway projects but inconsequential to others.

For example, snow and ice control will vary significantly among regions, and sustainable techniques that work in ice-prone northern Texas are likely quite different from those effective in the snow belt of upstate New York. The sustainability working group works to shed light on these potential discrepancies, bringing together viewpoints from across the Nation to ensure that FHWA's programs and tools are flexible enough to accommodate the full range of highway needs across the country.

Another challenge stems from the differences in urban and rural corridors. Bicycle and pedestrian facilities in urban areas, for example, are often different from those appropriate for rural areas; that is, a wider roadway shoulder may be appropriate in a rural area, while a sidewalk would be necessary in an urban area. In addition, the number of people affected by planning decisions regarding walking and bicycling access in roadway development is likely to be much greater in urban corridors than in rural ones. Similarly, dedicated wildlife crossings will not apply to many urban projects but are an important consideration in rural areas with high rates of collisions involving wildlife. FHWA's aim, therefore, is to provide universal metrics for measuring sustainability and to encourage participation by all who are interested.

What Makes a Sustainable Highway? U.S. 97, Deschutes National Forest, OR

Some of the United States' best existing examples of sustainable highways projects are in the national forests. As a result of the policies and funding for sustainability through the FHWA Office of Federal Lands Highway, a number of highway improvement projects spearheaded by the U.S. Forest Service have incorporated many sustainable highways principles.

The Oregon Department of Transportation's $16 million Lava Butte project on U.S. 97 in Deschutes National Forest included an array of efforts that support sustainability. Consisting of a 3.8-mile (6.1-kilometer) stretch of U.S. 97 in southern Oregon, the Lava Butte project involved expanding capacity from three lanes to four lanes, creating a forested median, developing a full diamond interchange (four on-/off-ramps), and improving access to the popular Lava Lands Visitor Center.

Specific sustainability efforts included the following:

  • Developing a construction quality plan that reviews all improvements to ensure adequate planning and completion of all efforts.
  • Paving with long-life pavements.
  • Constructing two wildlife underpasses to improve safety and allow for ecological connectivity.
  • Using recycled or repurposed construction materials whenever possible.
  • Developing facilities for safer access for bicyclists and pedestrians.
  • Planting native vegetation in the new median.
  • Using nonpotable effluent for all water-related activities except concrete.
  • Creating an information kiosk to inform visitors of the sustainable activities involved in the project.
Sustainable features of the U.S. 97 Lava Butte Project in Oregon include a wildlife connectivity underpass (left), an elevated tank containing nonpotable water (center), and an educational kiosk (right).
Sustainable features of the U.S. 97 Lava Butte Project in Oregon include a wildlife connectivity underpass (left), an elevated tank containing nonpotable water (center), and an educational kiosk (right).


This table lists the criteria used in INVEST's  Project Development module by principles and project scoring tool categories.
This table lists the criteria used in INVEST's Project Development module by principles and project scoring tool categories.

Source: FHWA.

Sustainable Pavements Program

Another related effort is FHWA's new Sustainable Pavements Program, initiated in fall 2010 to advance the knowledge and practice of sustainability in the pavements and materials area. The integrated program covers asphalt, concrete, granular, and recyclable materials used in pavement systems and promotes research into new sustainable materials and processes.

The goal is to support FHWA's livability and sustainability goals by raising the awareness and visibility of sustainability considerations in the design, construction, maintenance, and rehabilitation of pavement systems. Program objectives include developing guidelines for designing and constructing sustainable pavement systems; evaluating materials, processes, technologies, and tools to aid in the evaluation, design, and construction of sustainable pavement systems; and conducting technology transfer and deployment activities.

FHWA established a technical working group to provide input and feedback on pavement and material sustainability. The working group is composed of representatives from State DOTs, other government agencies, academia, and industry. "We are hopeful that we can address many sustainability issues faced by practitioners through open communication and information sharing," says Gina Ahlstrom, a pavement engineer at FHWA.

Many of the Sustainable Pavements technical working group members also played a role in the development of the pavement-related components of FHWA's INVEST tool.

What Makes a Sustainable Highway? Fernan Lake Road: Idaho Panhandle National Forest

In August 2008, the U.S. Forest Service embarked on a $14.6 million highway improvement project for Fernan Lake Road in the Coeur d'Alene District of the Idaho Panhandle National Forest. The primary purpose was to improve safety and stormwater management in a mountainous area prone to landslides and excessive runoff. Additional sustainability activities included the following:

  • Managing stormwater runoff to prevent contamination of wetlands and promote proper recharge of the water table.
  • Removing fill and building a bridge to create a wildlife underpass.
  • Using recycled and repurposed construction materials whenever possible.
  • Planting native vegetation to help stabilize steep slopes and minimize erosion.
  • Conducting environmental training so construction workers would be familiar with the intentions of their activities and the processes used.
  • Making all improvements within a context sensitive framework.
  • Developing a construction quality plan that reviews all improvements to ensure adequate planning and successful completion of all efforts.
Fernan Lake Road (left) in Idaho Panhandle National Forest is traversed by wildlife (center) as well as vehicles. During construction (right), workers recontoured the steep slopes to better manage stormwater runoff and groundwater recharge.
Fernan Lake Road (left) in Idaho Panhandle National Forest is traversed by wildlife (center) as well as vehicles. During construction (right), workers recontoured the steep slopes to better manage stormwater runoff and groundwater recharge.

Looking to the Future

For years, FHWA has supported research, development, and implementation efforts at the forefront of the sustainability movement. Now, with the creation of its sustainable highways program, FHWA hopes to consolidate those efforts under one umbrella.

As interest in sustainability principles and best practices among DOTs and the transportation industry continues to grow, FHWA will work to integrate INVEST into relevant future webinars, conferences, and National Highway Institute training courses. FHWA officials expect that the sustainable highways program will play a significant role in facilitating the creation and maintenance of the Nation's highway infrastructure in the years and decades ahead.

A highway improvement project on Happy Valley Road in Peoria, AZ included the reuse of existing pavements and structures, innovative contracting, native site vegetation, and resulted in a 4-mile (6.4-kilometer) urban arterial with sidewalks, bicycle lanes, and noise walls.


WSDOT's Approach to Sustainable Transportation

Moving Washington is the Washington State Department of Transportation's (WSDOT) decisionmaking framework for planning, operating, and investing in statewide transportation. It is focused on safety and preserving assets and includes three key strategies: operating the system more efficiently, managing transportation demand, and strategically adding capacity.

Moving Washington is also WSDOT's approach for creating an integrated 21st century transportation system that is reliable, responsible, and sustainable. Sustainable transportation supports a healthy economy, environment, and community and adapts to weather extremes, diminished funding, and changing priorities. Further, a sustainable transportation system is built to last, uses fewer materials and energy, and is operated efficiently.

To make the system more efficient, WSDOT works to smooth traffic flow and conserve resources by recycling and using fewer building materials. The department focuses on maintenance to extend the life of roads and bridges and plants native vegetation along roadsides, reducing maintenance and herbicides. To manage demand, WSDOT provides travel options by expanding ridesharing, transit, and pedestrian opportunities. WSDOT strategically adds capacity aligned with operational and demand management strategies. These efforts target the most congested traffic areas to reduce bottlenecks, complete corridor gaps, finish critical bridges, implement express lanes, and apply advanced technologies.

In addition, WSDOT is pursuing sustainable efforts in electric vehicle and alternative fuel facilities, as well as reducing energy consumption and transportation emissions. The department cochairs the development of a statewide integrated adaptation response and works with partners to integrate sustainable transportation strategies into plans and business practices. Recognizing the connections between land use and transportation, the department also seeks to leverage transportation investments to encourage land uses that are accessible to and promote a variety of travel modes.

Visit for more information.

Workers with the Washington State Department of Transportation are using warm-mix  asphalt paving for the first time on I–90 near George, WA. Warm-mix asphalt lowers the required temperature for processing at the plant and application at the jobsite, saving energy and cutting air emissions. It also can improve compaction.
Workers with the Washington State Department of Transportation are using warm-mix asphalt paving for the first time on I–90 near George, WA. Warm-mix asphalt lowers the required temperature for processing at the plant and application at the jobsite, saving energy and cutting air emissions. It also can improve compaction.


Workers applied lime to stabilize the existing subgrade and base in order to reduce earthwork needs during a project to reconstruct and widen the Jane Addams Memorial Tollway (I–90) near Rockford, IL in 2008.


Benjamin W. Cotton is a community planner with the Transportation Planning Division at the Volpe National Transportation Systems Center in Cambridge, MA. He has a B.A. from Kenyon College and a master's of city and regional planning from Clemson University.

For more information, visit, or contact Connie Hill at 804–775–3378 or, or Heather Holsinger at 202–366–6263 or Benjamin Cotton may be reached at 617–494–2608 or