Green highway

A green highway is a roadway constructed per a relatively new concept for roadway design that integrates transportation functionality and ecological sustainability. An environmental approach is used throughout the planning, design, and the construction. The result is a highway that will benefit transportation, the ecosystem, urban growth, public health and surrounding communities.
Research.
Green Highways Partnership (GHP) is an alliance of Federal Highway Administration (FHWA), U.S. Environmental Protection Agency (EPA), other Federal agencies, State transportation and environmental agencies, industry, trade associations, members of academia, and contractors to encourage environmentally friendly road building.
Another effort to create greener highways is a research program named Asphalt Research Consortium (ACR) created by collaboration of FHWA, private institutions, and several universities. The program studies potential ways to make asphalt more environmentally sustainable which will result in improved traffic safety and reduced life-cycle cost.
A 2019 research project from the Cooperative Research Program of the Transportation Research Board determined the state-of-practice in highway construction sustainability and produced a guidebook for practitioners as an aid in communicating, implementing, and evaluating sustainable highway construction. 
Benefits.
When built to standards of the concept, green highways have invaluable benefits to environment. Since they are built with permeable materials that provide superior watershed-driven stormwater management, leaching of metals and toxins into streams and rivers is prevented. Landfill usage is favorably reduced as construction involves recycled materials. In addition, by using cutting-edge technologies in design, critical habitats and ecosystems are protected from the encroachment of highway infrastructure.
Characteristics.
To develop a green highway, a project can follow guidelines provided below by GHP:
Other parameters associated with green highways and green roads include:
Technology.
Green highway construction can incorporate several technical elements including, but not limited to:
Examples.
U.S. Highway 301 Waldorf Transportation Improvements project is working towards becoming the nation’s first truly green highway by incorporating the principles of the Green Highways Partnership and green infrastructure in its earliest planning stages. The project encompasses an area from MD 5 and US 301 interchange in Prince George's County to the US 301 intersection with Washington Avenue and Turkey Hill Road in Charles County. It aims to improve the local traffic operation along US 301 while promoting and securing environmental stewardship.
Anacostia Watershed Protection: This pilot competition is designed to support the protection and restoration of urban water resources through a holistic watershed approach to water quality management. Funding will be directed to environmentally sound, watershed projects that stress a wide range of water quality improvement strategies and targets.