The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) revision submitted by the State of Maryland. This revision pertains to Maryland's incorporation by reference of the most recent amendments to California's Low Emission Vehicle (LEV) program. The Clean Air Act (CAA) contains authority by which other states may adopt new motor vehicle emissions standards that are identical to California's standards. Maryland has adopted by reference California's light and medium-duty vehicle emissions and fuel standards, and consistent with California, submits amendments to these standards as revisions to the State's SIP. In this SIP revision, Maryland is updating its Low Emissions Vehicle Program regulation to adopt by reference California's Advanced Clean Car Program. This action is being taken under the CAA.