Editing Environmental impact statement (section)

===Tiering===
On exceptionally large projects, especially proposed [[highway]], [[railroad]], and [[Public utility|utility]] [[Transport corridor|corridor]]s that cross long distances, the lead agency may use a two-tiered process prior to implementing the proposed action.  In such cases, the Tier I EIS would analyze the potential [[Environmental sociology|socio-environmental]] impacts along a general corridor, but would not identify the exact location of where the action would occur.  A Tier I ROD would be issued approving the general area where the action would be implemented.  Following the Tier I ROD, the approved Tier I area is further broken down into subareas, and a Tier II EIS is then prepared for each subarea, that identifies the exact location of where the proposed action will take place.  The preparation of Tier II EISs for each subarea proceeds at its own pace, independent from the other subareas within the Tier I area. For example, parts of the proposed [[Interstate 69]] extension in [[Indiana]] and [[Texas]], as well as portions of the [[Interstate 11]] corridor in [[Nevada]] and [[Arizona]] are being studied through a two-tiered process