Certifiable roads? Raising the standards for green infrastructure

At a time when sustainability is a buzzword in nearly every industry, the old maxim still holds true: you can’t manage what you can’t measure. Rating systems for green architecture have proliferated since LEED was launched in 1998 — designers can now choose from Passive House, BREEAM, CASBEE, and many more. These systems create accountability around sustainability goals in building design and construction. Now, rating systems for sustainable civil infrastructure — roads, tunnels, water, and the like — are burgeoning as well.

That’s good news, because in an urbanizing world, civil infrastructure’s impact on global carbon emissions will only increase. As a 2015 report commissioned by the C40 Cities Climate Leadership Group makes clear, unless we adopt a more sustainable approach to road networks and other infrastructure today, we’ll increase emissions by billions of tons for years to come. Getting new projects right the first time would likely also save money, preventing the need for expensive retrofits in a more carbon-conscious future.

New paths to sustainability

Two civil infrastructure rating systems have emerged in recent years to address the need. Greenroads, which accepted its first applicants in 2011, certifies transportation projects. Envision, developed the same year by the Institute for Sustainable Infrastructure (ISI), can be applied to infrastructure projects of any type and size.

At the time of this writing, Greenroads has certified 35 projects, while Envision has certified 15.


South Los Angeles Wetland Park, an Envision Platinum-rated project

A clear need leads to cross-sector collaboration

ISI is a nonprofit jointly founded by the American Society of Civil Engineers, the American Public Works Association, and the American Council of Engineering Companies with the sole purpose of administering Envision. These nonprofit organizations, which are deeply embedded in the US civil engineering profession, joined forces in the early 2000s to avoid developing competing systems. This led to collaboration with Harvard’s Zofnass Program for Sustainable Infrastructure, which was working on its own rating program at the time.

“Envision was originally primarily written by engineers,” said Denise Nelson, ISI’s vice president for public education. “There were a lot of engineers in the industry, like myself, that got the LEED accreditation. We could take one or two or three of the credits and apply it to different infrastructure projects, but you could never get a score and get an award.”

Greenroads, originally conceived by Martina Soderlund as part of her master’s degree in construction engineering, was developed to fill that same gap. Jeralee Anderson, today Greenroads’ executive director, took up the research in her own graduate work.

To develop the current system of requirements, the Greenroads team tested its ideas on 120 projects.

Massive potential

Anderson says Greenroads is driven by a startling statistic: the amount of energy it takes to build one lane of road 1 mile long is equal to the average annual energy usage of 100 American households. “That’s something we think is really important to understand because that is something we can control at the design and construction level,” she said. Simply using 20% recycled asphalt, for example, could lower that number to about 80 households. “That’s a pretty big impact you can actually measure.”

Working it out

Both Envision and Greenroads have already gone through several iterations, and both consist of multiple components: educational materials, professional training, and project certification.

Envision consists of 60 sustainability criteria that correspond with 60 possible credits, organized around five principles: quality of life, leadership, natural world, resource allocation, and climate and risk. An additional five credits reward innovation.

The amount of energy it takes to build one lane of road 1 mile long is equal to the average annual energy usage of 100 American households.

While the relevance of issues like resource allocation and climate is obvious, the quality of life and leadership credits deserve special mention, as they demonstrate foresight and a sensitivity to place and local stakeholders. This perspective represents a more fundamental shift.

“Sometimes with infrastructure, consultants or contractors come in at a point where owners say, ‘We want less congestion, so we’re going to add more lanes to get rid of traffic. Can you design it and build it?’” said Nelson. “[The quality of life credits] really make you sit back and think, ‘Is adding lanes the right solution to the problem of congestion, or would it be better to redesign the interchanges or add more interchanges, or build a light-rail system?’” In other words, “Is it in line with the community’s long-term plans?”

The leadership credits require similar soul-searching among the project team and stakeholders, including a willingness to look at the entire life cycle of a project. “We’re asking, ‘Is everyone committed to sustainability?’” said Nelson. “Are there resources we can set aside now to make sure that maintenance and operations are carried out properly?”

Envision credits and certifications

Envision’s credits are described in detail in a free guidance manual — essentially a textbook. ISI also offers several online tools that allow project members to evaluate how well they stack up.

If a project scores well, stakeholders can apply for third-party certification. Under this program, owners contract a third-party assessor to review how well the project meets the Envision criteria based on submitted documents.

Awards are granted based on percentage of total applicable credits achieved: 20% for Bronze, 30 for Silver, 40 for Gold, 50 for Platinum. Nelson said that while those percentages may sound low, the guidelines ask designers to go above and beyond conventional practice. Even 20% of credits achieved represents a significant decrease in environmental impact.

Because the criteria are also kept intentionally broad (so that they can be applied to all manner of infrastructure projects), it’s not possible to score 100%. For a particular project, credits may even be mutually exclusive. In remote areas, for example, it may be impossible to buy materials that are both local and recycled.

Projects that have received Envision awards thus far range from an Alaskan fish hatchery to a Brooklyn wastewater treatment facility.

Greenroads guides

Greenroads similarly doles out 130 total points in five categories: environment and water, access and livability, construction activities, materials and design, and utilities and controls . All projects must meet 12 basic project requirements, then obtain 30% of total points for Bronze, 38% for Silver, 46% for Gold, and 62% for Evergreen.

Smokey Point Transit Center

Arlington, Washington’s Greenroads Silver-certified Smokey Point Transit Center

Ideally, projects commit to pursuing certification once a project is certain to be built and has secured at least 50% of its funding, but before construction begins. At that point, the project team fills out a screening application and talks to Greenroads staff. If a project is determined likely to successfully meet certification requirements, it’s registered and appears on an online directory.

Neither Greenroads nor Envision offers technical support or advice about which credits to pursue or how, but both help users understand the system.

Looking to the future

Arup’s Frances Yang would like to see more government projects mandate the use of rating systems. While it’s “often seen as an added cost that not all public projects can really justify,” she believes that taxpayers will increasingly demand such treatment.

To spur this on, projects could initially be nudged with voluntary incentives while regulation is put in place. San Francisco used to offer permit fast-tracking for projects pursuing LEED, for example; now, nearly any project in the city above a certain square footage is required to be LEED Gold.

Presidio Parkway

San Francisco’s Greenroads Bronze-certified Presidio Parkway

Programs like this are slowly taking shape across the world. Tacoma, Washington, adopted a policy in 2014 requiring infrastructure projects of $5 million and above to strive for Greenroads Gold certification. The New Zealand Transport Agency is also using Greenroads.

Yang believes that Greenroads, with its narrow focus on roads, has been adopted more quickly than Envision, since project teams need more time to understand how the latter’s requirements can be adjusted to different infrastructure types.

In the meantime, projects get to set precedent. When working with Greenroads, Yang and her team have often given feedback on issues they believed needed more consideration. “It was good to see how a project can also influence the rating system,” she said.


Questions or comments for Jen Kinney or Frances Yang? Contact jkjenkinney@gmail.com or frances.yang@arup.com.

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