A report published on Tuesday by Florida TaxWatch warns that the state’s 2020 census undercount could have lasting consequences on federal transportation funding.

Florida was one of six states with a statistically significant census undercount, missing an estimated 750,000 residents, or 3.48 percent of the population. According to the report, the undercount will cost the state between $11 billion and $21 billion in federal funding over the course of the decade and may have cost Florida up to two congressional seats.

Among the more than 350 federal programs that use census data to guide funding decisions, 15 are within the U.S. Department of Transportation. These programs accounted for $93 billion in federal disbursements in fiscal year 2021 and include funding streams that support highway construction, transit systems, and traffic infrastructure maintenance.

“Transportation projects are already a big-ticket item for Florida taxpayers, comprising 13 percent of the state’s overall budget. As the state aims to budget adequate funding for transportation projects, an accurate census count is essential to draw down federal dollars that rightfully belong to the state of Florida,” said Florida TaxWatch Executive Vice President and General Counsel Jeff Kottkamp.

The Surface Transportation Block Grant Program, which falls under the Federal-Aid Highway Program, is one of the primary vehicles for distributing flexible federal funds to states and localities. In 2024, Florida received $718.3 million through the program, with $616.4 million available for population-based suballocations. The report found that 55 percent of those funds are allocated based on population within urbanized areas, making them sensitive to census miscounts.

Florida TaxWatch cited Port Charlotte–North Port as a case study. The area reported a population of 199,998 in the 2020 Census, just below the 200,000 threshold required for a higher funding classification. With a 2.1 percent estimated undercount, the area likely surpassed the threshold and could have received an additional $3 million in federal transportation funds.

The Urbanized Area Formula Grant, administered by the Federal Transit Administration, also relies heavily on census data. The grant provides capital and planning assistance for urban transit projects and determines allocations using factors including population, population density, and transit use. Undercounts in high-growth regions such as Miami–Fort Lauderdale, which experienced population increases but still recorded undercount rates of up to 7 percent, suggest those areas may be operating with less funding than needed.