Transportation plans shall include policies and provisions that promote the reduction of criteria pollutants. Transportation plans shall identify those aspects of the existing transportation system whose modification offers the best opportunity for improving air quality. Transportation plans shall include descriptions of the existing and proposed transportation system in sufficient detail, to permit conformity determinations using the criteria in WAC 173-420-060 and 173-420-065. Plans shall be analyzed with regional emission analysis for criteria pollutants. Local plans that are consistent under RCW 47.80.030 with a conforming regional transportation plan are deemed to comply with this chapter provided that the requirements of WAC 173-420-050 are met. Upon a conformity finding by the MPO, the plan shall be submitted to the United States Department of Transportation for federal conformity determination.