What is a purpose and need statement?
All EISs must contain a statement of purpose and need in accordance with 40 CFR § 1502.13. Consistent with NEPA, the purpose and need statement should be a statement of a transportation problem, not a specific solution. However, the purpose and need statement should be specific enough to generate alternatives that may potentially yield real solutions to the problem at-hand. A purpose and need statement that yields only one alternative solution may indicate a purpose and need that is too narrowly defined.

Every effort should be made to develop a concise purpose and need statement that focuses on the primary transportation challenges that need to be addressed. Although the purpose and need statement serves as a cornerstone for the development and evaluation of alternative, it should not discuss alternative solutions.

How can transportation planning be used to shape a project’s purpose and need in the NEPA process? 
A sound transportation planning process is the primary source of the project purpose and need. Through transportation planning, state and local governments (with involvement of stakeholders and the public) establish a vision for the region’s future transportation system; define transportation goals and objectives for realizing that vision; decide which needs to address; and determine the timeframe for addressing these issues. The transportation planning process also provides a potential forum to define a project’s purpose and need by framing the scope of the problem to be addressed by a proposed project. This scope may be further refined during the transportation planning process as more information about the transportation need is collected and consultation with the public and other stakeholders clarifies other issues and goals for the region.

The transportation planning process can be used to develop the purpose and need in the following ways:

1. Goals and objectives from the transportation planning process may be part of the project’s purpose and need statement;
2. A general travel corridor or general mode or modes (such as highway, transit, or a highway/transit combination) resulting from planning analyses may be part of the project’s purpose and need statement;
3. If the financial plan for an MPO’s long-range transportation plan indicates that funding for a specific project will require special funding sources (for example, tolls or public-private financing), such information may be included in the purpose and need statement; or
4. The results of analyses from management systems (for example, congestion, pavement, bridge, and/or safety) may shape the purpose and need statement.

The use of these planning-level goals and choices must be appropriately explained in the NEPA document, consistent with Appendix A to 23 CFR Part 450—Linking the Transportation Planning and NEPA Processes.

Additional Resources:
Federal Highway Administration, Environmental Review Toolkit, NEPA and Transportation Decisionmaking: The Importance of Purpose and Need in Environmental Documents, September 19, 1990
This paper discusses the basic ingredients of a purpose and need and how it is used in decisionmaking.

Federal Highway Administration, Environmental Review Toolkit, NEPA and Transportation 
Decisionmaking: Elements of Purpose and Need, September 19, 1990
This paper provides a list of items which could be covered in a purpose and need statement for a proposed action.

Council on Environmental Quality (CEQ) regulations for implementing NEPA (40 CFR Parts 1500 through 1508)

Federal Highway Administration/Federal Transit Administration Environmental Impact and Related Procedures (23 CFR Part 771)