(a) Define the types of actions that normally require an assessment of environmental impacts, including government-sponsored projects such as those receiving Federal financial assistance or permit approvals. (42 U.S.C. 4332(2)(C); 40 CFR 1501.1(a)(4), 1501.3, 1507.3(e)(2)(i), 1508.1(q);

(b) Ensure an early process for determining the scope of the action and issues that need to be addressed, identifying the significant issues, and for the classification of the appropriate assessment of environmental impacts in accordance with the significance of the likely impacts. For actions that may result in significant impacts on the environment, the scoping process must be an open and public process. (23 U.S.C. 139(e); 40 CFR 1501.5, 1501.9, 1506.6, 1507.3(c), 1507.3(e), 1508.1(y), and 1508.1(cc));

(c) Prohibit agencies and nongovernmental proponents from taking action concerning the proposal until the environmental impact evaluation is complete when such action would:

(d) Protect the integrity and objectivity of the analysis by requiring the agency to take responsibility for the scope and content of the analysis, and by preventing conflicts of interest among the parties developing the analysis and the parties with financial or other interest in the outcome of the project. (42 U.S.C. 4332(2)(D); 40 CFR 1506.5);

(e) Based on a proposed action's purpose and need, require objective evaluation of reasonable alternatives to the proposed action (including the alternative of not taking the action) if it may result in significant impacts to the environment or, for those actions that may not result in significant impacts, consideration of alternatives if they will involve unresolved conflicts concerning alternative uses of available resources (42 U.S.C. 4332(2)(C)(iii); 42U.S.C. 4332(2)(E); 23 U.S.C. 330(b)(1)(A); 40 CFR 1502.13, and 1502.14);

(f) Using procedures that ensure professional and scientific integrity of the discussions and analysis, require an assessment of the changes to the human environment from the proposed action or alternatives that are reasonably foreseeable and have a reasonably close causal relationship to the proposed action or alternatives. (42 U.S.C. 4332(2)(C); 23 U.S.C. 330(b)(1)(B); 40 CFR 1501.5(c)(2), 1502.16, 1502.23, and 1508.1(g);

(g) Require the consideration of appropriate mitigation for the impacts associated with a proposal and reasonable alternatives (including avoiding, minimizing, rectifying, reducing or eliminating the impact over time, and compensating for the impact) (40 CFR 1502.14(e), 1502.16(a)(9), and 1508.1(s));

(h) Provide for adequate interagency participation, including appropriate coordination and consultation with State, Federal, Tribal, and local agencies with jurisdiction by law, special expertise, or an interest with respect to any environmental impact associated with the proposal, and for collaboration that would eliminate duplication of reviews. For actions that may result in significant impacts to the environment, the process should allow for the development of plans for interagency coordination and public involvement, and the setting of timetables for the review process (42 U.S.C. 4332(2)(C); 23 U.S.C. 139(d) and 139(g); 40 CFR 1500.5(g), 1501.8, 1501.9(b), 1502.174, and part 1503);

(i) Provide an opportunity for public participation and comment that is commensurate with the significance of the proposal's impacts on the environment, and require public access to the documentation developed during the environmental review and a process to respond to public comments (42 U.S.C. 4332(2)(C); 23 U.S.C. 330(b)(1)(A); FAST Act, Sec. 1309(c)(2)(B)(ii); 40 CFR 1502.20, part 1503, and 1506.6; and Executive Order 11514, Sec.1(b));

(j) Provide for public access to the documentation necessary to review the potential impacts of projects;

(k) Include procedures for the elevation, resolution, and referral of interagency disputes prior to a final decision on the proposed project (23 U.S.C. 139(h); 40 CFR part 1504);

(l) For the conclusion of the environmental review process, require a concise documentation of findings (for actions that would not likely result in significant impacts to the environment) or, for actions that may result in significant impacts, a concise record that states the agency decision that:

(m) Require the agency to supplement assessments of environmental impacts if there are substantial changes in the proposal that are relevant to environmental concerns or significant new circumstances or information relevant to environmental concerns and have a bearing on the proposed action or its impacts. (23 U.S.C. 330(e)(3); 40 CFR 1502.9(d)); and

(n) Allow for the use of procedures to facilitate process efficiency, such as tiering, programmatic approaches, adoption, incorporation by reference, approaches to eliminate duplication with other Federal requirements, and special procedures to address emergency situations. Where the procedures allow for the identification and establishment of categories of actions that normally do not have a significant impact on the environment and are therefore excluded from further review, ensure that the procedures require the consideration of extraordinary circumstances that would warrant a higher level of analysis in which a normally excluded action may have a significant environmental effect. (23 U.S.C. 139(b)(3); 40 CFR 1500.4, 1500.5, 1501.4, 1501.11, 1501.12, 1502.24, 1506.2, 1506.3, and 1506.4).