Greenroads Manual

I-90 West of George Paving - Warm Mix Asphalt

The Washington State Department of Transportation (WSDOT) paved about 5,000 tons of warm mix asphalt (WMA) as part of their I-90 West of George Pav...

Frequently Asked Questions

Some of the more commonly asked questions we get.

What is Greenroads?

Greenroads is a sustainability performance metric for roadway design and construction. It is applicable to new and reconstructed/rehabilitated roadways. It awards credits for approved sustainable choices/practices and can be used to assess roadway project sustainability. This assessment can, if desired, include four different dertification levels depending upon total points earned.

Who is developing Greenroads?

The University of Washington and CH2M HILL are the Greenroads developers. Initial steps were taken at the University of Washington in 2007 by Martina Soderlund, a Valle Exchange master's student in Civil and Environmental Engineering. Since then the UW and CH2M HILL have teamed up to fully develop Greenroads.

Who is funding Greenroads?

See the Our Sponsors section of this website.

Any relation to the (fill in the blank here) rating system?

The answer is "not directly." here are now many green-type initiatives underway in the roadway business. They are at different levels of completion and address different aspects of sustainability and roads. Ulitmately, we are all working towards components of the same goal: more sustainable roads. Things like the Green Highways Partnership, GreenLITES, etc. are all striving towards this.

Aren't our roads already green?

Not really, however they are off to a good start. Many people, and rightfully so, point to the high use of reused and recycled materials in the roadway structure as evidence that roads are sustainable and/or environmentally responsible. While reused and recycled material use in roads is high (80% of old hot mix asphalt is recycled - one of the highest recycling rates of any material) there is much more we can do. For instance, the recycling rate could be much higher however most agencies limit the amount of reclaimed asphalt pavement (RAP) allowed in hot mix asphalt (HMA) to levels between 10 and 30%. While this is based on legitimate concerns, it is possible for the industry to increase this allowable amount through better RAP stockpiling, fractionating and tracking. Also, other aspects can be addressed or improved such as alignment to protect ecologically sensitive areas, construction waste reduction, diesel emission reduction during construction, noise mitigation (both during construction and during road use), stormwater control, life cycle assessment, urban heat island effects and low impact development techniques. In sum, improvement is a continuous and life-long process. There is no "good enough".

One should also consider the basic assumption we use in design and construction. Currently, the typical thought is to try and be "less bad" while we ought to be thinking how to actually be good; one of the points from William McDonough and Michael Braungart's Cradle to Cradle (2002).

Does the Washington State DOT use this standard now?

There is no official program or endorsement of Greenroads by WSDOT. Here at UW, we have always had a great working relationship with WSDOT and the Materials Laboratory there and that continues through this project where help has been valuable yet unofficial.

What is special about Greenroads vs. other potential standards?

We are aware of other ideas on sustainability and roads. We believe we stand out because:

We strive to make each best practice defensible through empirical evidence and sound engineering. If a credit is not defensible then we consider eliminating it. We would like to make the system more than just our opinion on what is and is not more sustainable. Thus, we expend great effort in tracking down empirical evidence that will guide us to what the best credits should be and how important they are.

Greenroads is weighted. Points are awarded for best practices that are commensurate with their impact on sustainability. We have submitted a paper to a respected journal discussing our weighting process.

We desire to make the submission and tracking process entirely online. Thus, this website.

What's up with the name? Greenroads or Green Roads?

The performance metric is called Greenroads. Yes, we originally called it "Green Roads", which we liked but enough feedback has come through to suggest that this could be interpreted as roads that are colored green or something like that. So, to put a bit more of a branding spin on things...(wait for it)...

...we removed the space and switched the "R" to lower case. Ahh, much better.Frankly, we like this better.

Does a Greenroad cost more?

Good question. The short answer is "we don't know". But, we are trying to find out. Taking a cue from Leadership in Energy and Environmental Design (LEED), a highly successful building rating system from the U.S. Green Building Council, we think the answer is probably that a Greenroads certified roadway actually costs less over its lifetime. This is essentially what others and the USGBC say about LEED certified buildings. And it's not too hard to believe considering LEED encourages things like energy efficiency, water conservation and creating a better working environment (that would lead to happier, more productive people).

Throughout 2010 and beyond we will attempt to gather data on pilot projects that documents what Greenroad credits do or could potentially cost vs. what their benefits are. We suspect things such as quality construction, designing pavement for long life, life cycle concepts, recycled materials and improved safety could show an overall lower life cycle cost. But the proof is in the data so we will just have to wait and see.

What's up with "rating system" vs. "performance metric"?

Yes, we used to call Greenroads a "rating system". However, upon further reflection, it is more than that. Fundamentally, it is a metric by which an organization can assess their project-level roadway sustainability efforts. Thus, "sustainability performance metric" is what it's called. Plus, "rating system" sounds like we would like to judge you but that's not what Greenroads is about. Rather, it is a tool that can be used as part of a greater organizational sustainability effort. That tool can help assess project-level roadway sustainability.

Can I get my project as a Greenroads pilot project?

We'd love to do every pilot project that asks. However, we, like everyone, have limited funds and personnel availability. If you would like to get your project looked at and possbly rated using Greenroads, take a look at the How to Get Your Project Reviewed document on the Resources: Learn & Talk page.

I would like to participate in reviewing and commenting on Greenroads version 1.0

You can do that. Just sign up online here and away you go. Great!

Who uses Greenroads and how many projects have been rated?

We came out with Version 1.0 in January 2010. There is no organization that has officially adopted Greenroads and there are no completed certified projects. However, we are working on about 20 case studies nationwide. These are projects where we are testing out Greenroads to see how it works and how it can be made better.So the bottom line is that Greenroads is brand new; we need some time to develop the infrastructure for review and certification. If you are interested in getting your project rated, we can do that in a consultant-type relationship. Please see: How to Get Your Project Reviewed.

Where is most of the interest in Greenroads coming from?

Everywhere. Owner agencies from all levels of DOTs in the United States, Canada and even internationally have expressed interest in using Greenroads on their projects. Interest is also coming from people in all different walks of life, from planners, to contractors, architects, and the public.