The Federal Highway Administration’s compliance with the National Environmental Policy Act (NEPA) calls for all environmental protection requirements and enhancement goals to be completed as part of a coordinated review process that includes and considers the input of other agencies and the public through established coordination and a public involvement process. Evidence of this compliance must be contained in appropriate documentation.
The purpose of documenting the NEPA process is twofold: to provide complete disclosure of the environmental analysis process, and to present the results of the analysis (i.e., the decision). Different kinds of transportation projects will have varying degrees of complexity or potential to affect the environment. The Council on Environmental Quality (CEQ) regulations implementing NEPA identifies three classifications of actions, defining the way that compliance with NEPA is documented in terms of the action's impacts:
- Categorical Exclusions are for actions that do not individually or cumulatively have a significant environmental effect.
- An Environmental Assessment is prepared for actions in which the significance of the environmental impact is not clearly established.
- An Environmental Impact Statement is prepared for projects where it is known that the action will have a significant effect on the environment.
Although the size and apparent complexity of the three levels of NEPA documentation is quite different, they all serve the same purpose, to achieve NEPA's goals of a collaborative decision making process and ultimately to make the public aware of the rationale behind transportation decisions.
The Council on Environmental Quality – Executive Office of the President determine the need for a guide that provides an explanation of NEPA, how it is implemented, and how people outside the Federal government can better participate in the assessment of environmental impacts conducted by Federal agencies. The result is A Citizen’s Guide to the NEPA: Having Your Voice Heard.