The primary law governing the Federal Transit Administration ’s environmental protection process is the National Environmental Policy Act of 1969 (NEPA). Many different federal laws, rules, and regulations govern environmental review of federally assisted transit projects. NEPA establishes an umbrella process for coordinating compliance with each law. This process may include an Environmental Assessment (EA) or an Environmental Impact Statement (EIS) for all major federal actions potentially affecting the environment (see What is an Environmental Assessment (EA)?).

NEPA establishes protection of the environment as a national priority and mandates that environmental impacts must be considered before any federal action likely to significantly affect the environment is undertaken. The Act has four primary purposes, including:

• Declaring a national environmental policy;
• Promoting efforts to protect the environment;
• Improving national understanding of environmental issues; and
• Establishing the Council on Environmental Quality.

The regulations of the Council on Environmental Quality (CEQ) implementing NEPA ensure that information on the social and environmental impacts is available to public officials and citizens before decisions are made and before actions are taken. NEPA regulations direct Federal agencies to integrate into their planning and decision making the natural and social sciences, environmental amenities and values, and the design arts along with the necessary engineering and economic considerations. The objective is to balance infrastructure development, economic prosperity, health and environmental protection, community and neighborhood preservation, and quality of life.