There are 3,980,817 miles of roads in the United States. Roads are the largest built structures we come into contact with and yet they are so ubiquitous and familiar that they have become an impervious given, the dark matter of the motor vehicle cosmos.
The amount of impervious roads is equivalent to the size of the state of Ohio. And the negative environmental impacts associated with those impervious surfaces are daunting.
Additionally, road building consumes a lot of energy. Building a one mile long single road lane uses as much energy to build as 50 American households in a single year.
But when society thinks about green building, those thoughts are almost universally of buildings (be it offices or schools or homes) and not of infrastructure like roads and bridges. As sustainability increasingly becomes a mainstream concern, one of the strategies some government departments of transportation have adopted for providing a more sustainable approach is a “green streets and highways rating system.”
Similar to LEED certification for buildings, emerging sustainability initiatives for roads are just beginning to pick up speed across the nation and there is no current widely accepted standard or practice for rating green roads.
Established in 2010 and gaining traction today, Greenroads Foundation is an independent nonprofit advancing sustainability education and initiatives for roads. As the developer of the Greenroads Rating System, the foundation manages the review and certification process for sustainable roadway and bridge construction projects in the U.S. and internationally.
The Greenroads rating system was the first third party, point based system available to certify sustainable roadway and transportation infrastructure projects. The system provides metrics to measure the effect of design and construction practices implemented on a project to earn points toward one of four awards, called "Ratings."
The Greenroads Rating System is a collection of sustainable roadway design and construction best practices that encompass water, environment, access, community impact, construction practices and materials. Each practice is assigned a point value according to its contribution to road sustainability.
At a minimum, there are 11 "Project Requirements” that must be completed in order for a road to be considered a Greenroad. There are also 37 "Voluntary Credits" that a project team can choose to pursue. Greenroads assigns a project score based on the number of points amassed by meeting the requirements and achieving credits. This score translates to one of four certification levels: Bronze, Silver, Gold and Evergreen. The Greenroads Manual is available without cost.
It is applicable to all types and sizes of road projects, including new, rehabilitation, reconstruction, preservation, overlay and bridge projects.
Greenroads provide environmental and economic benefits. In terms of lifecycle costs, a Greenroad costs less because the materials, technologies and systems used make it more durable, so it requires less and less environmentally damaging maintenance.
More than 100 projects of various types, sizes and stages of design and construction have been used as case studies to test and refine the Greenroads Rating System.
If green building is going to save the planet, society will have to think with a broader mindset than only buildings and Greenroads need to be at the forefront.