Greener Highways

When building and maintaining a safe and efficient surface transportation system, impacts on the natural and cultural environments are inevitable. But federal, state and local highway agencies are taking steps to integrate environmental sensitivity, which range from recycling old pavements and protecting watersheds during construction to involving community members and business leaders in the transportation decision-making process, into their day-to-day activities.

In 2002, the Federal Highway Administration (FHWA) designated environmental stewardship and streamlining as one of its three "vital few" goals, along with safety and congestion mitigation.

Subsequently, FHWA made substantial investments in improving the quality and efficiency of environmental decision-making through initiatives such as context sensitive solutions (CSS), the Eco-Logical approach, the Exemplary Ecosystem Initiatives program, the recently announced Human Environment Initiatives program and efforts to link planning and the environment.

The Green Highways Partnership is a voluntary, collaborative effort to foster partnerships to improve upon natural, built, social and environmental conditions while addressing transportation infrastructure requirements.

A MAP TO FOLLOW. After initial meetings and forums, a group of 40 representatives from the public and private sectors met to frame the future of Green Highways and to refine the road map for the partnership.

The group divided into three theme-focused teams after identifying the following focus areas offering the greatest potential to demonstrate Green Highways concepts:

"These areas are ripe for focus because of advancements in environmental science and technology," the American Concrete Pavement Association’s Robb Jolly says.

Raja Veeramacheneni, director of the Office of Planning and Preliminary Engineering at the Maryland State Highway Administration (SHA), adds that "to achieve successful outcomes, significant collaboration is needed to piece together aspects of a wide variety of laws, regulations, procedures, procurement methods and specification requirements. A functioning partnership is essential to develop timely solutions when obstacles arise."

A current focus of Green Highways is to implement pilot projects that demonstrate the concepts visibly and tangibly in the mid-Atlantic region. "Pilot projects will inform and inspire the implementation of practices and actions that are innovative, efficient, cost-effective and environmentally sound," says Veeramachaneni. "The anticipated outcome of the pilots is to demonstrate sustainable solutions and provide for market-based incentives," he continues. "Pilots also will serve to improve partnerships and research efforts. Green Highways serves as an opportunity to translate good ideas into practical realities."

ROADS TO RECYCLING. The recycling and reuse team is focusing on efforts in a number of areas. First, it is identifying existing regulations and specifications. The team then will develop state performance standards and specifications for voluntary use of recycled materials in highways.

The team also is collecting and disseminating information to increase use of recycled products and developing opportunities to exchange best practices. In addition, the team will produce a tool kit to provide technical information and guidance to help DOTs (departments of transportation) overcome hurdles.

Another priority is to identify state DOT projects that optimize the beneficial reuse of industrial byproducts. To date, Maryland, Pennsylvania, Virginia and West Virginia have been targeted for pilot projects to showcase beneficial reuses in their states.

As each state offers ongoing stewardship examples, Green Highways will help increase the visibility of these activities and their use on more projects. For example, the Pennsylvania DOT constructed the Tarrytown Bridge using shredded tires as lightweight embankment fill on two bridge approaches. The project incorporated approximately 780,000 scrap tires, thereby easing the load on landfills.

In West Virginia, the DOT is using recycled blast furnace slag as the aggregate of choice in the western part of the state for the majority of asphalt surface course pavements. The effort results in a safer pavement in light of the aggregate’s non-polishing properties (higher friction number).

According to Jason Harrington, an asphalt pavement engineer with FHWA, with an open-graded friction in course aggregate like slag, the roadway does not experience as much spray or misting during rain, offering better visibility and much less hydroplaning.

Further, recycling blast furnace slag, which is available locally in western West Virginia, offers an economic advantage compared with using virgin limestone aggregate.

"Although the coarseness in slag increases friction, which is highly desirable, the size of the aggregate [pieces] are larger, which contributes to a slight increase in noise levels. When noise is a concern, the use of smaller aggregate sizes (0-6 millimeters or 0-10 millimeters) is recommended," says Chris Corbisier, FHWA highway traffic noise specialist.

A GREENER MARYLAND. In addition to the pilot efforts under development within each theme area, the partnership is looking to apply Green Highways concepts in a more comprehensive manner. Toward that goal, the Maryland SHA recently volunteered to apply an environmental stewardship approach to a transportation improvement project by implementing the following key actions:

In keeping with the collaborative nature of Green Highways, SHA is planning a design charrette to investigate potential green approaches, technologies and actions. "This project will provide an opportunity to integrate all of the principles and concepts of Green Highways into a single project and has the potential to serve as a model for other projects in the mid-Atlantic and across the country," says SHA’s Veeramachaneni.

This story was excerpted from an article that originally appeared in the FHWA’s Nov.-Dec. 2006 issue of Public Roads magazine. The author is an environmental protection specialist with the FHWA Office of Project Development and Environmental Review. She can be reached at marlys.osterhues@fhwa.dot.gov.