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State DOTs Use New Technologies to Reduce, Reuse and Recycle


By Mark S. Kuhar

Earth Day goes hand in hand with raising environmental awareness – and this year the American Association of State Highway and Transportation Officials is using the occasion to share the many ways our members are protecting the environment.

“State transportation departments are finding ways to strike a balance between building the highways, bridges and mass transit systems America desperately needs, while being responsible environmental stewards,” said John Horsley, AASHTO executive director. “Earth Day is an excellent time to draw attention to the many state DOT success stories that might otherwise go untold.”

States are utilizing a comprehensive approach to minimize their carbon footprint, save precious resources and protect and preserve sensitive ecosystems.

California
The California Department of Transportation (Caltrans) is dramatically reducing energy usage while improving safety by installing 40,000 LED street lights to replace existing fixtures over a two-year period.

The cost of the lights is estimated to be between $25 million and $30 million (not including rebates). These units require 60 percent less electricity than their predecessors and will reduce lighting demand by 4.5 megawatts, saving taxpayers an estimated $2 million in annual energy costs.

Oklahoma
The Oklahoma Department of Transportation (ODOT) is embarking on a first-of-its-kind, large-scale, bridge recycling project. This past February when ODOT opened the new Crosstown Expressway in Oklahoma City, it took the I-40 Crosstown Bridge out of service. Instead of tearing down and scrapping the 47-year-old structure, ODOT decided to recycle the bridge, awarding a $10 million contract to deconstruct it.

North Carolina
This past fall, the North Carolina Department of Transportation (NCDOT) implemented a change in policy that allows for the recycling of residential roof shingles in the production of asphalt pavement.

About 260,000 tons of used shingles went into landfills last year. If this many shingles were diverted from landfills, the annual cost savings would be about $32 million. NCDOT's new policy is preventing a portion of these shingles from entering landfills statewide, and helping the department to cut costs at the same time.

Florida
The Florida Department of Transportation (FDOT) estimates that by July of this year, an array of more than 400 solar panels will provide 70 percent of the electricity used at its new Turnpike retail facility at the Turkey Lake Service Plaza. Eight Turnpike service plazas are undergoing a $162 million renovation.

The new facilities are being designed and built using strategies to gain Leadership in Energy and Environmental Design (LEED) certification by the U.S. Green Building Council. LEED certification provides independent, third-party verification that a building is achieving high performance in key areas of human and environmental health.

Nevada
In 2011, the Nevada Department of Transportation resurfaced Interstate 15 using pavement made from approximately 20 percent ground, recycled rubber tires. With the flexibility of rubber incorporated into new asphalt, ride smoothness nearly doubles and roadway surface deterioration is reduced.

Arizona
The Arizona Department of Transportation (ADOT) has repurposed more than 15 million recycled tires as part of a technique it calls “Quiet Paving.” Engineers estimate that approximately 1,500 tires are used per lane mile of rubberized asphalt paving. The technique was most recently used on Interstate 17 north of Loop 101 in Phoenix and on U.S. 60 west of Phoenix.

Idaho
In 2011, the Idaho Transportation Department (ITD) began work on a $1.2 million fish-passage project near Lowman. The U.S. Forest Service determined that a culvert at that location was blocking fish and other aquatic species from swimming upstream to Five Mile Creek. ITD removed the 300-ft. long, 72-in. wide culvert and replaced it with a 125-ft. wide pre-stressed concrete girder bridge, opening up the entire Five Mile Creek watershed to a healthier, more balanced ecosystem. The project, which is being funded by the U.S. Forest Service, will be completed early this year.