EPA is taking final action to extend the grace period before the MOtor Vehicle Emission Simulator (MOVES) model is required for regional emissions analyses for transportation conformity determinations ("regional conformity analyses"). This final rule provides an additional year to the previously established two-year conformity grace period. As a result, EPA is announcing in this Federal Register that MOVES must be used for new regional conformity analyses that begin after March 2, 2013. This action does not affect EPA's previous approval of the use of MOVES in state air quality implementation plan (SIP) submissions or the existing grace period before MOVES is required for carbon monoxide and particulate matter hot-spot analyses for project-level conformity determinations (75 FR 79370).