The Environmental Protection Agency (EPA) is taking direct final action to approve two revisions to the Maryland State Implementation Plan (SIP). The Clean Air Act (CAA) provides authority allowing California to adopt its own motor vehicle emissions standards for newly manufactured vehicles, in lieu of federal vehicle standards. The CAA also allows other states to adopt California's vehicle standards, as long as they are identical to California's standards. Maryland's recent SIP submittals serve to amend Maryland's Clean Car Program to incorporate updates that California has made to its Low Emission Vehicle (LEV) program rules. Maryland adopted California's emission standards applicable to newly manufactured light and medium-duty vehicles in 2007, and EPA approved Maryland's Clean Car Program in prior rulemakings. However, since then California revised its LEV program regulations on several occasions, and Maryland subsequently amended its own rules to be consistent with those of California. Since the Clean Car Program is part of the SIP, Maryland then submits these amendments as a SIP revision. Maryland submitted such SIP revision requests in July 2014 and again in April 2015 to update its SIP to be consistent with California's latest LEV program rules. EPA's action to approve Maryland's most recent Clean Car Program SIP revisions is being taken under the CAA.