For an MPO that has previously been attainment and subject to the 5-year plan update requirement, but is now nonattainment under the 8-hour ozone and/or PM2.5 standards, how do they transition to the 3-year plan/conformity update cycle?
The MPO must demonstrate conformity of its transportation plan and TIP within one year of the effective date of the nonattainment designation (June 15, 2004 for 8-hour ozone and April 5, 2005 for PM2.5). If an area has a valid plan in place (i.e., within the 5-year planning cycle for attainment areas), the area can demonstrate conformity on their existing plan provided that they meet all other requirements. However, the conformity determination will only be good for the rest of the life of the plan (i.e., if less than 3 years left in the plan, the plan will expire/lapse on its 5 year scheduled update) or 3 years after the conformity determination, whichever comes first. Alternatively, they can make a conformity determination on a brand new plan by the end of the grace period which will start the 3-year clock. Q2: For an MPO that has previously been nonattainment or maintenance for the 1-hour standard and subject to the 3-year plan/conformity update requirement, but will now be attainme
