Illinois has joined the ranks of states that allow their public road projects to use an asphalt mix that includes recycled shingles.

Saying, "We can't keep throwing things into landfills," Illinois Gov. Pat Quinn signed legislation Friday that will help turn old roofing shingles into asphalt for new road surfaces on public projects around Illinois.

Like most green initiatives, environmental advantages are just some of the benefits. The ability to reduce costs is an attractive argument for further recycling. With asphalt being created mostly from petroleum, the price savings on raw materials alone is significant. The Missouri Department of Transportation reports approximately $20 million in savings in 2009 by using recycled shingles in their hot-mix.

Overall, about 1 million tons of reclaimed asphalt shingles went into new hot-mix last year, according to the National Asphalt Paving Association. That's less than 10% of the total waste stream, but a big jump over previous years.

"This law will keep more shingles out of landfills, benefit the environment and save the state millions of dollars by expanding our use of recycled materials," said Gov. Quinn in the Peoria Journal Star.

It is also creating a few jobs: Southwind RAS, a shingle recycling facility that opened in Peoria, Illinois this year, intends to establish eight more recycling facilities across the state.

Although the reuse of shingles in asphalt pavement is a new idea in many states, it has been used in the US for over 20 years.

Colorado's nascent shingle recycling effort last year diverted over 50,000 tons of asphalt shingles from landfills, according to a local roofing blog.

"Shingle recycling has grown tremendously in the past 10 years," said William Turley, executive director of the Construction Materials Recycling Association, a trade group. He estimates that one-third of the waste is currently recycled, and expects that to continue rising.

The patchwork of state regulations has been a hindrance to the advancement of recycling efforts, however, and is not systematically tracked by any private or government agency.

Find a shingle recycling facility in your state. Go to ShingleRecycling.org and click on your state from the list on the left.