Congestion Mitigation and Air Quality Improvement Modernization Act This bill revises the apportionment formula used to distribute funds under the federal-aid highway system for the congestion mitigation and air quality improvement program to include population data and recent Environmental Protection Agency (EPA) air pollution data for ozone and fine particulate matter. The bill also provides a state flexibility to use apportioned funds if such state does not have, and never has had, a nonattainment area designation under the Clean Air Act. ( A nonattainment area is one that does not meet the national primary or secondary ambient air quality standards established by the EPA.)