U.S. Environmental Protection Agency

April 2001

Document Released for Public Information

"Determination of Methane Offsets as a
Function of Mileage for Light-Duty Cars and Trucks" 

Report Number   EPA420-R-01-031     (M6.EXH.006)
 
	The Office of Transportation and Air Quality, Assessment and 
Standards Division announces the release of "Determination of Methane Offsets as a
Function of Mileage for Light-Duty Cars and Trucks" for public 
information.  This document EPA420-R-01-031, also known as M6.EXH.006, 
is available at the MOBILE6 section of the OTAQ Web Site 
(http://www.epa.gov/otaq/m6.htm).

	This document describes methodologies for calculating for the 
MOBILE6 model a methane emission factor "offset" based on the 
separation of start and running emissions.  Results from the underlying data
and the proposed methane emission factor 'offsets' are presented.  

	This report was originally released (as a draft) in October 
1997, and then revised in January, 2001.  This current 
version is the final revision of the January, 2001 draft (of M6.EXH.006).  
This final revision incorporates suggestions and comments received 
from stakeholders during the 60-day review period and from peer 
reviewers.