CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 52—APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS > SUBPART NN—Pennsylvania (§52.2020 to §52.2063) > 52.2057—Requirements for state implementation plan revisions relating to new motor vehicles.