This legislation introduces a mechanism to provide discretionary increases in highway funding for states experiencing population growth. It authorizes the Secretary of Transportation to allocate additional funds to states that have seen their population rise since the previous decennial census, with the amount based on the relative increase in each state's population. This aims to ensure that federal highway resources can better adapt to the infrastructure demands of growing regions. The bill also mandates a comprehensive highway formula modernization study , to be conducted by the Secretary of Transportation in consultation with state departments of transportation and local governments. This study will assess the current method and data used to apportion federal-aid highway funds, evaluating whether it achieves an equitable distribution based on estimated tax payments from highway users and general fund contributions. It will also determine if the current formula effectively meets national transportation goals. As part of the study, the Secretary must consider various factors, including historical apportionment criteria and the availability and accuracy of data. Based on this assessment, the Secretary is tasked with developing recommendations for a new apportionment method , detailing the factors to be included and their appropriate weighting. A report containing the study's findings and these recommendations must be submitted to Congress within 90 days of the Act's enactment.