Today EPA promulgates a clarified and more flexible transportation conformity rule. The conformity rule requires that transportation plans, programs, and projects conform to state air quality implementation plans (SIPs) and establishes the criteria and procedures for determining whether or not they do. Conformity to a SIP means that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the national ambient air quality standards. The conformity rule changes promulgated today result from the experience that EPA, the Department of Transportation (DOT), and state and local air and transportation officials have had with implementation of the rule since it was first published in November of 1993. While these changes clarify the rule and in some cases offer increased flexibility, they will not result in any negative change in health and environmental benefits. Today's rule gives state and local governments more authority in selecting the performance measures used as tests of conformity and more discretion when a transportation plan does not conform to a SIP. For example, the rule allows motor vehicle emissions budgets in a submitted SIP to be used to determine conformity instead of the ``build/no- build'' test, and rural areas can choose among several conformity tests to address the time period after that covered by the SIP.