The guidance is required by Section 187 (a) of the Clean Air Act Amendments of 1990. It offers the Environmental Protection Agency's (EPA's) recommendations on how to forecast and track vehicle miles traveled (VMT) in Moderate and Serious carbon monoxide (CO) non-attainment areas with design values greater than 12.7 ppm at the time of classification. The purpose of the guidance is to help states prepare State Implementation Plan (SIP) revisions that EPA can readily propose to approve as meeting the requirements of the Clean Air Act Amendments. If a state adheres to the guidance, EPA will propose approval of its SIP. A state intending to depart from the guidance, however, should show that the alternative approach it proposes is technically sound and adequate to meet the requirements of the Clean Air Act Amendments. EPA will review SIP submittals from such states on a case-by-case basis to determine whether they do in fact comply with the Clean Air Act Amendment requirements. States are encouraged to obtain EPA approval before using methods other than those specified in the guidance, in order to avoid later problems.

Publisher information came from the cover. Publisher location came from U.S. EPA About EPA, Mailing addresses and phone numbers webpage. "January 1992." "EPA/420-R-92-008."