Linking Planning & NEPA

Transportation corridor studies typically contain a general statement of a future vision for the corridor that is focused on transportation goals. This vision statement may be able to be re-used during NEPA analysis as the project purpose and need statement if it contains certain elements, including consideration of specific goals for the corridor, multiple objectives (beyond transportation); vetting by agencies and the public; and a more specifically defined corridor geography. The figure below illustrates the differences between a typical corridor study vision and goals and NEPA purpose and needs statement. If the study direction changes significantly between the development of the corridor vision and the inception of NEPA analysis, it may become necessary to develop a new purpose and need statement.


FHWA has suggested a list of considerations in a Purpose and Need Statement in Guidance for Preparing and Processing Environmental and Section 4(f) Documents. The list is not all-inclusive and is only meant as a guide.

  • Project Status
  • System Linkage
  • Capacity
  • Transportation Demand
  • Legislation
  • Social Demands or Economic Development
  • Modal Interrelationships
  • Safety
  • Roadway Deficiencies

Caltrans assembled the Purpose and Need Quality Team to improve the process of preparing well-defined purpose and need statements for transportation projects. This team created a purpose and need website with guidance and tools on purpose and need statements to help planners, designers, and managers prepare quality purpose and need statements that are appropriate to each stage of project planning and delivery.

The Idaho Corridor Planning Guidebook (2006) outlines the steps needed to produce a written statement of purpose and need for corridor projects. This statement should be an “umbrella” statement for the corridor based on the identification of needs and deficiencies. The statement should reflect the principles of context sensitivity by encouraging the consideration of land use, transportation, environmental, and infrastructure needs in an integrated manner.