Transportation Conformity Rule Amendments: Minor Revision of 18-Month Requirement for Initial SIP Submissions and Addition of Grace Period for Newly Designated Nonattainment Areas

EPA is promulgating two minor revisions to the transportation conformity rule. Transportation conformity is required by the Clean Air Act to ensure that federally supported highway and transit project activities are consistent with ("conform to") the purpose of a state air quality implementation plan (SIP). Conformity to the purpose of the SIP means that transportation activities will not cause new air quality violations, worsen existing violations, or delay timely attainment of the national ambient air quality standards. EPA's transportation conformity rule establishes the criteria and procedures for determining whether transportation activities conform to the state air quality plan. First, today's final rule will implement a Clean Air Act amendment that provides a one-year grace period before conformity is required in areas that are designated nonattainment for a given air quality standard for the first time. This Clean Air Act amendment was enacted on October 27, 2000. Although the grace period is already available to newly designated nonattainment areas as a matter of law, EPA is today incorporating the one-year conformity grace period into the conformity rule. Second, today's final rule will change the point by which a conformity determination must be made following a State's submission of a control strategy implementation plan or maintenance plan for the first time (an "initial" SIP submission). Today's rule requires conformity to be determined within 18 months of EPA's affirmative finding that the SIP's motor vehicle emissions budgets are adequate. Prior to today's action, the conformity rule required a new conformity determination within 18 months of the submission of an initial SIP. This change to the conformity rule better aligns when the 18-month requirement for conformity to initial SIP submissions is implemented, so that state and local agencies have sufficient time to redetermine conformity when initial SIPs are submitted and after EPA finds the SIP bu