March 9, 1999

Document Released for Stakeholder Review and
Comment

Guidance for the Development of Facility Type VMT
and SpeedDistributions

Report Number EPA420-P-99-004
The Office of Mobile Sources, Assessment and
Modeling Divisionannounces the release of 

"Guidance for the Development of Facility Type VMT
and Speed Distributions" for stakeholder review
and comment.  This document
EPA420-P-99-004 also known as M6.SPD.004.is
available at the MOBILE section of the OMS Web
Site (http://www.epa.gov/oms/m6.htm)

This draft guidance is provided to assist users of
the MOBILE6 highway vehicle emission factor model
in the preparation of traffic activity inputs. It
offers the U.S. Environmental Protection Agency's
(EPA) recommendations on how to develop
distributions of vehicle miles traveled (VMT) by
time of day, facility type and average speed.
These distributions will be required by MOBILE6
for the development of an area wide emission
factor for light duty vehicles, as well as
facility-specific emission factors. 

Although national default distributions have been
developed, there is sufficient variation in
roadway network characteristics between areas that
the use of locally developed distributions is
strongly preferred. In almost all urbanized areas,
some local data will be available that can be used
to develop improved activity inputs for MOBILE6
The methods presented here were developed based on
a  review of locally available data and tools that
could support facility-specific VMT and speed
estimates and existing transportation planning
tools and methods.

Comments on this report and its proposed use in
MOBILE6 should be sent to the attention of Dave
Brzezinski .  Comments may be submitted
electronically to mobile@epa.gov,by fax to (734)
214- 4939, or by mail to MOBILE6 Review Comments,
US EPA Assessment and Modeling Division, 2000
Traverwood Drive, Ann Arbor, MI 48105.  Electronic
submission of comments is preferred.  In your
comments, please note clearly the document that
you are commenting on, including the report title
and the code number listed.  Please be sure to
include your name, address, affiliation and any
other pertinent information.

This document is being released and posted on
March 9,1999. Comments will be accepted until May
10, sixty (60) days after date of posting.  EPA
will then review and consider all comments
received and will provide a summary of those
comments and how we are responding to them in the
form of a follow-up document.

Thank you for your continuing interest in the
development of MOBILE6.

Sincerely,

Emission Inventory Group, Assessment and Modeling
Division, US EPA Office of Mobile Sources