There are three classes of actions that prescribe the level of documentation required in the NEPA process. A programmatic approach may be used for any class of action.

EIS (Class I). Actions that significantly affect the environment require an EIS (40 CFR 1508.27). The following are examples of actions that normally require an EIS:

A new controlled access freeway.

A highway project of four or more lanes on a new location.

Construction or extension of a fixed transit facility (e.g., rapid rail, light rail, commuter rail, bus rapid transit) that will not be located primarily within an existing transportation right-of-way.

New construction or extension of a separate roadway for buses or high occupancy vehicles not located within an existing transportation right-of-way.

New construction or extension of a separate roadway for buses not located primarily within an existing transportation right-of-way.

New construction of major railroad lines or facilities (e.g., terminal passenger stations, freight transfer yards, or railroad equipment maintenance facilities) that will not be located within an existing transportation right-of-way.

CE (Class II). Actions that do not individually or cumulatively have a significant environmental effect are excluded from the requirement to prepare an EA or EIS. A specific list of CEs normally not requiring NEPA documentation is set forth in § 771.117(c) for FHWA actions or pursuant to § 771.118(c) for FTA actions. When appropriately documented, additional projects may also qualify as CEs pursuant to § 771.117(d) for FHWA actions or pursuant to § 771.118(d) for FTA actions. FRA's CEs are listed in § 771.116.

EA (Class III). Actions for which the Administration has not clearly established the significance of the environmental impact. All actions that are not EISs or CEs are EAs. All actions in this class require the preparation of an EA to determine the appropriate environmental document required.