# Measurement and calculation procedures.
**AGENCY:**
National Highway Traffic Safety Administration (NHTSA), Department of Transportation (DOT).
**ACTION:**
Correcting amendments.
**SUMMARY:**
This document contains corrections to the final rule regulations (49 CFR 535.6), which were published in the *Federal Register* of Thursday, September 15, 2011 (76 FR 57106). The regulations established fuel efficiency standards for medium- and heavy-duty engines and vehicles, as prescribed under the Energy Independence and Security Act (49 U.S.C. 32902(k)(2)).
**DATES:**
*Effective Date:* November 14, 2011.
**FOR FURTHER INFORMATION CONTACT:**
Lily Smith, Office of Chief Counsel, National Highway Traffic Safety Administration, 1200 New Jersey Avenue, SE., Washington, DC 20590. *Telephone:* (202) 366-2992.
**SUPPLEMENTARY INFORMATION:**
**Background**
NHTSA and EPA published in the *Federal Register* of September 15, 2011, final rules to establish a comprehensive Heavy-Duty National Program that will increase fuel efficiency and reduce greenhouse gas emissions for on-road heavy-duty vehicles, responding to the President's directive on May 21, 2010, to take coordinated steps to produce a new generation of clean heavy-duty vehicles.
**Need for Correction**
As published, the final regulations inadvertently contained incorrect conversion factors for determining fuel consumption values that resulted from a typographical error. The correct value that should have been used in the document is a factor of 8,887 grams of CO <sub>2</sub> per gallon of gasoline for conversion of gasoline fuel. The preamble text is not affected.
**List of Subjects in 49 CFR Part 535**
Fuel efficiency.
Accordingly, 49 CFR part 535 is corrected by making the following correcting amendments:
**49 CFR Part 535**
**PART 535—MEDIUM- AND HEAVY-DUTY VEHICLES**
1. The authority citation for part 535 continues to read as follows:
**Authority:**
49 U.S.C. 32902; delegation of authority at 49 CFR 1.50.
**49 CFR Part 535**
2. Revise paragraphs (a)(4)(ii) and (c)(4)(ii) of § 535.6 to read as follows:
§ 535.6
(a) * * *
(4) * * *
(ii) Calculate the equivalent fuel consumption test group results as follows for spark-ignition vehicles and alternative fuel spark-ignition vehicles. CO <sub>2</sub> emissions test group result (grams per mile)/8,887 grams per gallon of gasoline fuel) × (10 <sup>2</sup> ) = Fuel consumption test group result (gallons per 100 mile).
(c) * * *
(4) * * *
(ii) Calculate equivalent fuel consumption FCL values for spark-ignition engines and alternative fuel spark-ignition engines. CO <sub>2</sub> FCL value (grams per bhp-hr)/8,887 grams per gallon of gasoline fuel) × (10 <sup>2</sup> ) = Fuel consumption FCL value (gallons per 100 bhp-hr).
Issued: September 22, 2011.
Christopher J. Bonanti,
Associate Administrator for Rulemaking, National Highway Traffic Safety Administration, Department of Transportation.