U.S. Environmental Protection Agency

November 2001

Document Released for Public Information

"Determination of Start Emissions as a Function of Mileage and
 Soak Time for 1981-1993 Model Year Light-Duty Vehicles"

Report Number   EPA420-R-01-058     (M6.STE.003)
 
	The Office of Transportation and Air Quality, Assessment and 
Standards Division announces the release of "Determination of Start Emissions as a 
Function of Mileage and Soak Time for 1981-1993 Model Year Light-Duty Vehicles" 
for public information.  This document EPA420-R-01-058, also known as M6.STE.003,
is available at the MOBILE6 section of the OTAQ Web Site 
(http://www.epa.gov/otaq/m6.htm). 

	MOBILE6 will allocate vehicle exhaust emissions to either
those associated with engine start (start emissions) or those
associated with travel (running emissions). This document
describes the methodology used to estimate start emissions as a
function of mileage and soak time for Tier 0 (i.e., 1981-1993
model year) light-duty cars and trucks, and presents the
estimates proposed for use in MOBILE6.

	This report was originally released (as a draft) on May, 1999 
under the title, "Determination of Start Emissions as a Function of Mileage and 
Soak Time for 1981-1993 Model Year Light-Duty Vehicles".  It was subsequently 
revised in November, 2001, and the November, 2001 is now the final version.  
This final revision incorporates suggestions and comments received from stakeholders 
during the 60-day review period and from peer reviewers.