23 CFR § 771.113 - Timing of Administration activities.
(a) The lead agencies, in cooperation with the applicant and project sponsor, as appropriate, will perform the work necessary to complete the environmental review process. This work includes drafting environmental documents and completing environmental studies, related engineering studies, agency coordination, public involvement, and identification of mitigation measures. Except as otherwise provided in law or in paragraph (d) of this section, final design activities, property acquisition, purchase of construction materials or rolling stock, or project construction must not proceed until the following have been completed:
(ii) The Administration has issued a FONSI; or
(iii) The Administration has issued a combined final EIS/ROD or a final EIS and ROD;
(b) For FHWA actions, completion of the requirements set forth in paragraphs (a)(1) and (2) of this section is considered acceptance of the general project location and concepts described in the environmental review documents unless otherwise specified by the approving official.
(c) Letters of Intent issued under the authority of 49 U.S.C. 5309(g) are used by FTA to indicate an intention to obligate future funds for multi-year capital transit projects. Letters of Intent will not be issued by FTA until the NEPA process is completed.
(d) The prohibition in paragraph (a)(1) of this section is limited by the following exceptions:
(1) Early acquisition, hardship and protective acquisitions of real property in accordance with 23 CFR part 710, subpart E for FHWA. Exceptions for the acquisitions of real property are addressed in paragraphs (c)(6) and (d)(3) of § 771.118 for FTA.
(2) The early acquisition of right-of-way for future transit use in accordance with 49 U.S.C. 5323(q) and FTA guidance.
(3) A limited exception for rolling stock is provided in 49 U.S.C. 5309(l)(6).
(4) FRA may make exceptions on a case-by-case basis for purchases of railroad components or materials that can be used for other projects or resold.