§ 51.394 - Applicability.

(a) Action applicability. (1) Except as provided for in paragraph (c) of this section or § 51.460, conformity determinations are required for:

(i) The adoption, acceptance, approval or support of transportation plans developed pursuant to 23 CFR part 450 or 49 CFR part 613 by an MPO or DOT;

(ii) The adoption, acceptance, approval or support of TIPs developed pursuant to 23 CFR part 450 or 49 CFR part 613 by an MPO or DOT; and

(iii) The approval, funding, or implementation of FHWA/FTA projects.

(2) Conformity determinations are not required under this rule for individual projects which are not FHWA/FTA projects. However, § 51.450 applies to such projects if they are regionally significant.

(b) Geographic applicability. (1) The provisions of this subpart shall apply in all nonattainment and maintenance areas for transportation-related criteria pollutants for which the area is designated nonattainment or has a maintenance plan.

(2) The provisions of this subpart apply with respect to emissions of the following criteria pollutants: ozone, carbon monoxide, nitrogen dioxide, and particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM10).

(3) The provisions of this subpart apply with respect to emissions of the following precursor pollutants:

(i) Volatile organic compounds and nitrogen oxides in ozone areas;

(ii) Nitrogen oxides in nitrogen dioxide areas; and

(iii) Volatile organic compounds, nitrogen oxides, and PM10 in PM10 areas if:

(A) During the interim period, the EPA Regional Administrator or the director of the State air agency has made a finding that transportation-related precursor emissions within the nonattainment area are a significant contributor to the PM10 nonattainment problem and has so notified the MPO and DOT; or

(B) During the transitional, control strategy, and maintenance periods, the applicable implementation plan (or implementation plan submission) establishes a budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy.

(c) Limitations. (1) Projects subject to this regulation for which the NEPA process and a conformity determination have been completed by FHWA or FTA may proceed toward implementation without further conformity determinations if one of the following major steps has occurred within the past three years: NEPA process completion; start of final design; acquisition of a significant portion of the right-of-way; or approval of the plans, specifications and estimates. All phases of such projects which were considered in the conformity determination are also included, if those phases were for the purpose of funding, final design, right-of-way acquisition, construction, or any combination of these phases.

(2) A new conformity determination for the project will be required if there is a significant change in project design concept and scope, if a supplemental environmental document for air quality purposes is initiated, or if no major steps to advance the project have occurred within the past three years.

(d) Grace period for new nonattainment areas. For areas or portions of areas which have been in attainment for either ozone, CO, PM-10, or NO2 since 1990 and are subsequently redesignated to nonattainment for any of these pollutants, the provisions of this subpart shall not apply for such pollutant for 12 months following the date of final designation to nonattainment.