1. Short title This Act may be cited as the Congestion Mitigation and Air Quality Improvement Modernization Act . 2. Apportionment Section 104(b)(4) of title 23, United States Code, is amended to read as follows: (4) Congestion mitigation and air quality improvement program (A) Calculation For the congestion mitigation and air quality improvement program, an amount determined by multiplying the amount of the base apportionment remaining for the State under subsection (c) after making the set aside in accordance with paragraph (5) by the proportion that— (i) the total of all weighted county populations with monitored pollutant concentrations above national ambient air quality standards in the State; bears to (ii) the total of all weighted county populations with monitored pollutant concentrations above national ambient air quality standards in all States. (B) Calculation of weighted populations with monitored pollution concentrations above national ambient air quality standards Subject to subparagraphs (C), (D), and (E), for the purpose of subparagraph (A), the weighted population in counties with pollution concentrations above national ambient air quality standards shall be calculated by multiplying the population of each county by a factor determined from the ratio of design values to national ambient air quality standards. (C) Design values of ozone (i) In general In making the calculation under subparagraph (B), for counties with design values of ozone greater than the national ambient air quality standard, the population of a monitored county is multiplied by a factor of— (I) the average of 2013–2015 and 2016–2018 design values, provided by the Environmental Protection Agency Administrator