The following definitions will apply unless a different meaning is clearly required by context:

"Criteria pollutants" means air pollutants for which a NAAQS has been promulgated under the federal Clean Air Act (40 C.F.R. 50) and their precursors and, for this chapter, applies only to those pollutants for which nonattainment or maintenance areas have been designated.

"Action scenario" means the future transportation system determined pursuant to the federal transportation conformity regulation (40 C.F.R. Part 51 Subpart T) in a year that is being analyzed for conformity that will result from the implementation of the proposed plan and/or transportation improvement program.

"Baseline scenario" means the transportation system determined pursuant to the federal transportation conformity regulation (40 C.F.R. Part 51 Subpart T) in a year that is being analyzed for conformity that would result from the plan, improvement program, and facilities, services, and activities that are in effect in the year the conformity analysis is being conducted.

"Lead agency" means the agency with primary responsibility for ensuring plan, program, or project compliance with SEPA, (chapter 197-11 WAC).

"Maintenance area" means any geographic region of the United States previously designated nonattainment pursuant to the CAA Amendments of 1990 and subsequently redesignated to attainments subject to the requirement to develop a maintenance plan under section 175A of the CAA, as amended.

"Metropolitan area boundary" (MAB) means an area determined by an agreement between the governor and the MPO as defined in 23 U.S.C. 134.

"Metropolitan planning organization" (MPO) means an organization for each urbanized area of more than fifty thousand people as defined in 23 U.S.C. 134, whose responsibilities include development of transportation plans and improvement programs for those areas.

"Motor vehicle emission budget" means that portion of the total allowable emission defined in a state implementation plan for a certain date for the purpose of meeting attainment or maintenance demonstrations for any criteria pollutant or its precursors, that is allocated by the SIP to highway and transit vehicles.

"National ambient air quality standards" (NAAQS) means air quality standards promulgated for criteria pollutants under the federal Clean Air Act (40 C.F.R. 50). The standard for carbon monoxide is thirty-five parts per million over a one-hour period or nine parts per million over an eight-hour period. The standard for ozone is 0.12 parts per million over a one-hour period. The standard for PM10 is fifty µg/m3 annual arithmetic mean or 150 µg/m3 maximum twenty-four hour average concentration.

"Nonattainment area" means the geographic area designated as not meeting the NAAQS for a criteria pollutant. The boundaries are proposed by the governor, approved by the federal Environmental Protection Agency (EPA), and include that area required to implement plans and programs for attainment of the NAAQS published in the federal register.

"Regional transportation system" means the transportation system identified by an MPO in development of planning requirements under the federal Intermodal Surface Transportation Efficiency Act (ISTEA) (P.L. 102-240).

"Regionally significant project" means a transportation project that is on a facility which serves regional transportation needs and would normally be included in the modeling of a metropolitan area's transportation network, including at a minimum all principal arterial highways and all fixed guideway transit facilities that offer an alternative for regional highway travel.

"State implementation plan" (SIP) means a plan as defined in section 302(q) of the CAA and which implements the relevant requirements of the CAA that is intended to eliminate or reduce the severity and number of violations of the national ambient air quality standards and expeditiously achieve those standards, and includes the revision referred to as the maintenance plan that provides for the maintenance of the NAAQS in the area concerned for at least ten years after the redesignation of a nonattaiment area to an attainment area.

"Transportation control measure" (TCM) means a transportation project, program, or action listed in the state implementation plan that will aid in elimination or reduction of the severity or number of violations of the national ambient air quality standards and help expeditiously attain and maintain those standards.

"Transportation improvement program" (TIP) means a schedule of intended transportation improvements (or continuation of current activities) as required in section 134 of Title 23 U.S.C. A TIP shall include projects within the MPO's area that are proposed for funding under Title 23 U.S.C. and the federal Transit Act, projects that are part of or consistent with the transportation plan as previously defined, and transportation control measures that are included in the state implementation plan for meeting NAAQS.

"Transportation plan" means a document that is required under the regulation implementing section 134 of Title 23 U.S.C., and section 8 of the federal Transit Act, and is intended to foster a continuing, cooperative, and comprehensive planning process.

"Transportation projects" means an action that expends funds on or approves physical and/or operational alterations to a transportation system.