EPA is granting conditional approval of a State Implementation Plan (SIP) revision submitted by the State of Maryland. This revision establishes and requires the implementation of an enhanced motor vehicle inspection and maintenance (I/M) program in the counties of Anne Arundel, Baltimore, Calvert, Carroll, Cecil, Charles, Frederick, Harford, Howard, Montgomery, Prince George's, Queen Anne's, Washington, and the City of Baltimore. The intended effect of this action is to conditionally approve the Maryland enhanced motor vehicle I/M program. EPA is conditionally approving Maryland's SIP revision based on the fact that: Maryland's SIP is deficient in certain aspects with respect to the requirements of the Act and EPA's I/M program regulations, and Maryland has made a commitment in a letter, dated December 23, 1996, to work with EPA to address and correct all deficiencies as necessary to ensure full compliance with I/M requirements by a date certain within one year from September 2, 1997. This action is taken under section 110 of the 1990 Clean Air Act (CAA, or the Act).