Now Greenroads - Rating system for Sustainable Road Construction.

The Greenroads evaluation of the impact of US road building is a step in the right direction, but still has miles to travel

America has 10% of the the planet's roads and building each mile of freeway uses as much energy as 200 US homes in a year.

With 4m miles of highway, the USA has around 10% of the entire planet's paved roads – and spends $85bn (£52bn) annually on rolling out tens of thousands more miles. Building and maintaining a single mile of freeway takes as much energy as 200 US homes use in a year, consumes as much raw material as 1,000 households get through in 365 days and generates more waste than 1,200 homes produce annually.

Now University of Washington researchers and engineering firm CH2M Hill have launched the world's first rating system for sustainable road construction, along the lines of the LEED programme for green buildings. Greenroads evaluates a road's overall environmental and social impact, taking into account everything from construction materials and practices to noise pollution, habitat control and bike lanes. Projects have to fulfil basic building, waste, pollution, lifecycle and outreach plans, and can then earn extra points for using recycled or local resources, reducing their reliance on fossil fuels, minimising water use and implementing smart traffic management systems.

"We are trying to be very inclusive and address the range of roadway projects," says Steve Muench, assistant professor of civil and environmental engineering at the University of Washington. "For example, in an urban project you might spend a lot of time and effort building a surface that lasts decades with minimum maintenance or reduces tyre noise. In a rural environment, you might be more focused on treating stormwater and including wildlife crossings."

The Greenroads system already has the support of five US state departments of transport and the University is following 15 case study projects to see how its ratings system affects energy usage, carbon footprint and – where the rubber hits the road – cost. "We think it may cost a little more upfront but if you look at the total lifecycle cost of that road, you'll be miles ahead," says Muench. "I look at what has happened with green buildings. It started out as completely voluntary but it's evolved over the last decade and now nearly 300 government and education agencies have policies that all their new buildings must be LEED-certified. In that sense, it's no longer voluntary, it's no longer an option: it's required. With Greenroads, we want to push the industry in the right direction."

Road builders point out that they have already embraced some eco-friendly practices. The Portland Cement Association claims to have reduced energy usage by nearly 40% over the last 40 years, says 2m tons of recycled aggregate are now used in roads annually, and has ensured a less energy-intensive "warm mix" of asphalt is gradually becoming more widely used. But with 95% of aggregates still being mined fresh from the ground and highway spending forecast to increase 8% this year, America seems a long way from ever building truly sustainable roads.

"Right now, we're on the side of the scale where we produce waste that is not very useful, we use more than we put back and we're altering ecosystems more than we should," admits Muench. "With Greenroads, we're basically trying to get a point where we're doing less evil."

Source: http://www.guardian.co.uk/environment/2010/jan/19/greenroads-us-road-construction-environment