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Lifecycle of a project - Enviro review & prelim design

Environmental review and preliminary design: takes 1 - 4 years

This phase identifies potential environmental impacts of the alternatives, allows for public comment and provides information for the Board to consider in selecting the project to be built. The project's design moves from conceptual to preliminary.

The level of review and documentation depends on the scope of the project and its potential for environmental impacts.

  • An Environmental Impact Statement (EIS) is prepared for large projects with potentially significant impacts.
  • An environmental assessment, State Environmental Protection Act (SEPA) checklist or other document may be prepared for projects not requiring an EIS. 

During this phase:

  • Field work may include observing and counting traffic, studying natural resources and land use and monitoring noise.
  • If required, a Draft EIS is published followed by a public comment period. Responses to those comments are found in the Final EIS.
  • Preliminary design is completed.
  • The Sound Transit Board selects the project that will eventually be built.
  • For federalized projects requiring an EIS, the lead federal agency issues an environmental decision document, called a Record of Decision (ROD).