Section 450.340 - Phase-in of new requirements(a) Prior to May 27, 2018, an MPO may adopt a metropolitan transportation plan that has been developed using the SAFETEA-LU requirements or the provisions and requirements of this part. On or after May 27, 2018, an MPO may not adopt a metropolitan transportation plan that has not been developed according to the provisions and requirements of this part.(b) Prior to May 27, 2018 (2 years after the publication date of this rule), FHWA/FTA may determine the conformity of, or approve as part of a STIP, a TIP that has been developed using SAFETEA-LU requirements or the provisions and requirements of this part. On or after May 27, 2018 (2 years after the publication date of this rule), FHWA/FTA may only determine the conformity of, or approve as part of a STIP, a TIP that has been developed according to the provisions and requirements of this part, regardless of when the MPO developed the TIP.(c) On and after May 27, 2018 (2 years after the issuance date of this rule), the FHWA and the FTA will take action (i.e., conformity determinations and STIP approvals) on an updated or amended TIP developed under the provisions of this part, even if the MPO has not yet adopted a new metropolitan transportation plan under the provisions of this part, as long as the underlying transportation planning process is consistent with the requirements in the MAP-21.(d) On or after May 27, 2018 (2 years after the publication date of this rule), an MPO may make an administrative modification to a TIP that conforms to either the SAFETEA-LU or to the provisions and requirements of this part.(e) Two years from the effective date of each rule establishing performance measures under 23 U.S.C. 150(c) , 49 U.S.C. 5326 , and 49 U.S.C. 5329 FHWA/FTA will only determine the conformity of, or approve as part of a STIP, a TIP that is based on a metropolitan transportation planning process that meets the performance based planning requirements in this part and in such a rule.(f) Prior to 2 years from the effective date of each rule establishing performance measures under 23 U.S.C. 150(c) , 49 U.S.C. 5326 , or 49 U.S.C. 5329 , an MPO may adopt a metropolitan transportation plan that has been developed using the SAFETEA-LU requirements or the performance-based planning requirements of this part and in such a rule. Two years on or after the effective date of each rule establishing performance measures under 23 U.S.C. 150(c) , 49 U.S.C. 5326 , or 49 U.S.C. 5329 , an MPO may only adopt a metropolitan transportation plan that has been developed according to the performance-based provisions and requirements of this part and in such a rule.(g) A newly designated TMA shall implement the congestion management process described in § 450.322 within 18 months of designation.81 FR 34135, May 27, 2016, as amended at 81 FR 93473, Dec. 20, 2016; 82 FR 56545, Nov. 29, 2017 81 FR 34135, 6/27/2016; as amended at 81 FR 93473, 12/20/2016; 82 FR 56545, 12/29/2017