104 STAT. 2472 PUBLIC LAW 101-549—NOV. 15, 1990 PART B—OTHER PROVISIONS Sec. 231. Ethanol substitute for diesel. Sec. 232. Adoption by other States of California standards. Sec. 233. States authority to regulate. Sec. 234. Fugitive dust. Sec. 235. Federed compliance. PART A—AMENDMENTS TO TITLE II OF CLEAN AIR ACT SEC. 201. HEAVY-DUTY TRUCKS. Section 202(a)(3) of the Clean Air Act (42 U.S.C. 7521(a)(3)) is amended as follows: (1) Strike subparagraphs (A), (B), (C), (D), and (E) and insert the following: Regulations. "(A) IN GENERAL. — (i) Unless the standard is changed as provided in subparagraph (B), regulations under paragraph (1) of this subsection applicable to emissions of hydrocarbons, carbon monoxide, oxides of nitrogen, and particulate matter from classes or categories of heavy-duty vehicles or engines manufactured during or after model year 1983 shall contain standards which reflect the greatest degree of emission reduction achievable through the application of technology which the Administrator determines will be available for the model year to which such standards apply, giving appropriate consideration to cost, energy, and safety factors associated with the application of such technology. "(ii) In establishing classes or categories of vehicles or engines for purposes of regulations under this paragraph, the Administrator may base such classes or categories on gross vehicle weight, horsepower, type of fuel used, or other appropriate factors. "(B) REVISED STANDARDS FOR HEAVY DUTY TRUCKS.—(i) On the basis of information available to the Administrator concerning the effects of air pollutants emitted from heavy-duty vehicles or engines and from other sources of mobile source related pollutants on the public health and welfare, and taking costs into account, the Administrator may promulgate regulations under paragraph (1) of this subsection revising any standard promulgated under, or before the date of, the enactment of the Clean Air Act Amendments of 1990 (or previously revised under this subparagraph) and applicable to classes or categories of heavy- duty vehicles or engines. "(ii) Effective for the model year 1998 and thereafter, the regulations under paragraph (1) of this subsection applicable to emissions of oxides of nitrogen (NOJ from gasoline and dieselfueled heavy duty trucks shall contain standards which provide that such emissions may not exceed 4.0 grams per brake horsepower hour (gbh). "(C) LEAD TIME AND STABILITY. —Any standard promulgated or revised under this paragraph and applicable to classes or categories of heavy-duty vehicles or engines shall apply for a period of no less than 3 model years beginning no earlier than the model year commencing 4 years after such revised standard is promulgated. "(D) REBUILDING PRACTICES. — The Administrator shall study the practice of rebuilding heavy-duty engines and the impact
�
