Small Transit Communities Modernization Act This bill modifies the definition of eligible area for purposes of the grant program under the small transit intensive cities formula to include an urbanized area with a population of at least 200,000, but not more than 999,999. The modification extends through FY2030. Before apportioning grant funds for any urbanized area that is no longer an eligible area due to a change in population, the Department of Transportation must apportion to such area, for three fiscal years, an amount equal to half of the funds the area received in the previous fiscal year.