What Are Motor Vehicle Emissions Budgets?
As described in CAA section 176(c)(2)(A), attainment demonstrations necessarily include estimates of motor vehicle emissions to help areas reach attainment. These estimates act as a budget or ceiling for emissions from motor vehicles, and are used in conformity to determine whether transportation plans and projects conform to the attainment SIP. In order for transportation plans and projects to conform, estimated emissions from transportation plans and projects must not exceed the emission budgets contained in the attainment demonstration. 3. Which Motor Vehicle Emissions Budgets Usually Apply? According to the transportation conformity rule, motor vehicle emissions budgets in a submitted SIP apply for conformity purposes even before we have approved the SIP, under certain circumstances. First, there must not be any other approved SIP motor vehicle emissions budgets that have been established for the same time frame and with respect to the same CAA requirements. For example, if there i
