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Faculty & research

Greenroads: Sustainability Performance Metrics for Roadway Design and Construction

For most communities, roads are essential to sustainability. They are huge economic drivers and allow the mobility and freedom central to our way of life. If miles are one measure of economic impact, it is huge: the U.S. has more than four million miles of roads, and worldwide the total exceeds 40 million.

image of a ribbon

On the downside, roads require significant amounts of material, equipment, and space and have a substantial ecological impact. Constructing and maintaining one lane-mile of freeway pavement can use 7,000 to 12,000 tons of raw materials, consume 3 to 8 TJ (terra Joules) of energy, emit 500 to 1,200 tons of CO2 equivalent expressed as Global Warming Potential (GWP), and generate 2,500 tons of waste. While we are beginning to move aggressively toward sustainability in building construction, the energy sector, and even the automobile industry, we have largely ignored transportation infrastructure.

Civil & Environmental Engineering’s research efforts can help "green" America's roads. One effort, led by Assistant Professor Steve Muench, is developing Greenroads, a rating system that assesses the sustainability of new, reconstructed, and rehabilitated roads. Like several prior rating systems, including the LEED system for buildings, Greenroads awards credits for approved sustainable choices and can be used to certify projects.

Greenroads provides three benefits: (1) a holistic way to consider roadway sustainability, (2) a defined and quantitative means to assess sustainability, and (3) a tool that allows decision-makers, agencies, consultants, and contractors to make informed design and construction decisions. The ultimate goal is to create the nationwide rating system of choice.

"Interest in this system is growing quickly," Muench said. "We are in early negotiations to test the system on about 15 potential projects to help answer some key questions, such as: How much does it cost to use the rating system? What needs to be improved or changed?"

The Greenroads project evolved from master's thesis work by Martina Soderlund (MS 2007, now at Stantec). The current research team includes CEE and UW students Jeralee Anderson, Yen Yu Lin, Chris Croft, Mac McCarthy, Jared Koester, Josh Hatfield, Paul Prigge, Rosslyn Luke, and Nick Jones. Sponsors include TransNow, the State Pavement Technology Consortium (DOT representatives from Washington, California, Minnesota, and Texas), and the Western Federal Lands Highway Division in Vancouver, Wash.

You can download the Greenroads manual at www.greenroads.us.

This article appears in the spring 2009 issue of The Bridge, the newsletter of UW's Department of Civil & Environmental Engineering.