Sustainable Infrastructure

USTMA Supports Sustainable Infrastructure

Sustainable Infrastructure

Why Sustainable Infrastructure Is Needed

  • Rebuilding America’s roadways should be done with the future in mind to develop roadways that increase driver safety and ensure reductions in environmental impacts.
  • USTMA supports federal and state initiatives that advance the development of sustainable green infrastructure to build roadways for a sustainable future.

USTMA is encouraged by the documented benefits of rubber modified asphalt, stormwater infiltration galleries and rain gardens (or bioswales). USTMA supports additional scientific research into these projects to better understand their long-term benefits, performance and environmental impacts.

Rubber Modified Asphalt

  • Adding ground rubber from scrap tires into asphalt appears to have many benefits for drivers, neighborhoods, and state departments of transportation. Studies to date show the benefits of adding ground rubber scrap tires to asphalt include:
    • Quieter pavement, better grip, and less spray for drivers in wet weather.
    • Longer lasting roads that crack and rut less than traditional asphalt leading to better long-term cost effectiveness.
    • Promotes the circular economy as asphalt itself is one of the most recycled products in the U.S. and rubber modified asphalt can be recycled in the same way.
  • Cal Recycle is researching water runoff from rubber modified asphalt verses traditional asphalt. 

Stormwater Infiltration Galleries

  • The use of tire derived aggregate, or large shreds of scrap tires, in stormwater infiltration galleries also appears to provide significant benefits in reducing pollutants entering stormwater in urban areas. [1]
  • Stormwater infiltration galleries are patches of material through which stormwater flows before entering a storm drain.
  • CalRecycle research found that galleries made with tire derived aggregate reduce stormwater pollutants such as zinc and iron by over 80%[2] and research by the University of Minnesota found stormwater galleries with tire chips reduce pollutants in stormwater runoff by over 60%.[3]

Rain Gardens (Bioswales)                                

  • Rain Gardens, also referred to as Bioswales, are shallow drainage ditches that slow water movement and capture particulate pollutants during rainstorms. Examples include:
  • A collaboration between The Ray (a non-profit “living lab”), Georgia Department of Transportation, and local ecologists created a “highway of the future,” which includes bioswales made from native plants.[4]
  • Washington State University and Stewardship Partners are leading a cooperative effort to plant 12,000 rain gardens in Puget Sound (over 6,000 have been added so far).[5]

[2] CalRecycle Presentation “Civil Engineering Applications Using TDA” at 12, 16 (2017).

[3] University of Minnesota Report: “The Impact of Stormwater Infiltration Practices on Groundwater Quality” at 58 (2014).

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