MoDOT is embracing new greener technologies that are saving the department some green as well.

When resurfacing highways, MoDOT has traditionally used a type of asphalt that requires extremely high temperatures - 300 degrees Fahrenheit - to produce. Now it is using warm-mix asphalt on some projects, which lowers the temperature needed for production by up to 100 degrees. With decreased production temperatures come lower emissions, some by 70 percent, from burning fuels, fumes, and odors generated at the plant and at the paving site.

A cleaner environment is just one benefit. The lower temperatures used to produce warm-mix asphalt also improve pavement density, which lengthens a road's life. The stronger the road, the longer it lasts, resulting in less money spent for repair or replacement work. We also save taxpayers an average of 10 to 30 cents per ton when using warm-mix asphalt versus traditional hot-mix asphalt, because less energy is used to get it ready for the road.

Another positive feature of warm-mix asphalt is that it extends the work year. Traditionally, a paving schedule starts in April and ends in October. Because warm-mix asphalt works well in colder temperatures, it allows paving work to stretch from March through December.

While warm-mix asphalt is proving its worth, MoDOT still continues to beef up its efforts to make hot mix asphalt projects more economical and environmentally friendly, too.

With the number of contractors in Missouri using recycled asphalt and tear-off shingles growing, so are the number of projects using them as a hot mix asphalt material. In 2009, MoDOT used a half-million tons of reclaimed asphalt pavement (a process known as Hot In-Place Recycling) and 53,000 tons of recycled asphalt shingles: enough roofing material to cover the tops of nearly 17,000 homes.

These recycling efforts saved MoDOT $20 million on highway projects last year alone. Beyond that, MoDOT reduced the amount of petroleum it used in its road construction program by 20 percent and significantly cut down the amount of shingles that went into Missouri landfills.

The asphalt mixture has proven to be very durable, more rut resistant and lower in cost - factors that can't be ignored in a highly competitive contracting environment. Check out other ways MoDOT recycles at www.modot.org/goinggreen.