As set forth by the National Environmental Policy Act (NEPA), the Federal Highway Administration (FHWA) is committed to the examination and avoidance of potential impacts to the social and natural environment when considering approval of proposed transportation projects. Potential environmental impacts can vary based on the type, size and complexity of the project. Effects can vary from very minor to significant impacts on the local environment. To account for the variability of project impacts, three basic "classes of action" are allowed and determine how compliance with NEPA is carried out and documented:
Environmental Impact Statements (EIS): An EIS breaks down the project development process of a transportation project, which includes the consideration of a range of reasonable alternatives, analyzes the potential impacts resulting from the alternatives, and demonstrates compliance with other applicable environmental laws and executive orders.
Environmental Assessments (EA): An EA is prepared if the significance of impacts of a project is deemed uncertain. If significant impacts are found as a result of the EA, then the preparation of an EIS should begin. If no impacts are determined, a Finding of No Significant Impact (FONSI) must be prepared.
Findings of No Significant Impact (FONSI): If the EA determines there will be no significant impacts from the project, a Findings of No Significant Impact (FONSI) to conclude the process and document the decision.
Categorical Exclusion (CE): A CE is prepared when a category of actions do not individually or cumulatively have a significant effect on the environment. This means that neither an EA nor EIS is required.
In preparation of these documents, a variety of studies are completed, which are summarized in the NEPA documents. Studies may be completed for the following subjects:
Cultural Historic: As a result of Section 106 of the National Preservation Act of 1966, federal agencies are required to consider impacts to historic properties when making project decisions. Sites greater than 50 years of age are required to be identified and evaluated for eligibility by the National Register of Historic Places (NRHP). If a project results in an Adverse Effect, the agencies and consulting parties involved will determine appropriate ways to avoid, minimize, or mitigate the impact.
Hazardous Materials: A survey of the project area is done to identify any sites with potential hazardous materials or underground storage tanks. A study is done to compare possible impacts and the appropriate mitigation measures for affected sites.
Socioeconomic: Socioeconomic analysis considers the potential for impacts to land use, the economy, farmlands, residential and commercial relocations, recreational and community resources and sensitive populations. Once these impacts are identified enhanced public involvement efforts and appropriate mitigation for these protected communities are incorporated in the project development process.
Noise: Transportation projects can create noise impacts on neighboring properties. Current and predicted noise conditions are evaluated to determine impacts as a result of a new highway project. Before construction of a project begins, noise data is collected, traffic volume is estimated, and with the use of the FHWA Traffic Noise Model, potential impacts of traffic noise are predicted.
Air Quality: Increased traffic is accompanied by increased vehicle emission. To determine the effects that a transportation project will have on air quality, carbon monoxide, particulate matter and mobile source air toxics are evaluated. They are then tested to ensure that the additional traffic associated with the project will not increase the amount of pollutants in the area.
Terrestrial & Aquatic: Transportation projects may impact terrestrial and aquatic ecosystems. To determine potential impacts, coordination with agency officials (including the U.S. Fish and Wildlife Service, the Kentucky Department of Fish and Wildlife), various records studies and field surveys of aquatic and terrestrial habitat and species are completed. Once the impacts are determined, recommendations are made to prevent, minimize or mitigate the possible impacts.
For more information, please visit http://www.environment.fhwa.dot.gov