When the Biden administration created a grant program three years ago to fund transportation projects explicitly dedicated to promoting “neighborhood access and equity,” officials in St. George, Utah, saw an opportunity.

They had long sought funding to build two underpasses to bridge the interstate highway dividing the city in half, creating chronic traffic jams around a pair of schools. So when the president of the United States prioritized equity in transportation projects, city officials submitted a grant for a project that the administration later highlighted as crucial to breaking “a vehicle dependency that is often disproportionately borne by marginalized communities.”

The Biden administration awarded them $87 million.

Then came Republican control of Washington, and President Trump’s initiative to root out “radical and wasteful government D.E.I. programs.” Republicans in Congress pushed through a sprawling domestic policy bill that rescinded all money awarded through the Biden-era transportation program that had not yet been spent — $3.2 billion in total, including all the funding awarded to St. George.

Representative Sam Graves of Missouri, the chairman of the Transportation Committee, hailed the rollback as “cutting wasteful Green New Deal spending.”

All told, funding was yanked back for 55 projects, 19 of which had been set to be built in Republican congressional districts, according to federal data obtained by The New York Times. They included rebuilding highways, new underpasses and overpasses, and pedestrian and bike trails. The biggest included in G.O.P.-held districts included $147 million to design and build a 30-mile trail in Jacksonville, Fla., represented by Representative Aaron Bean; and $74.9 million to rebuild a highway in Missoula, Mont., represented by Representative Ryan Zinke; and the project in St. George, represented by Representative Celeste Maloy.

The little-noticed cancellations were yet another instance in recent months of Republican members of Congress aligning themselves with Mr. Trump’s ideological agenda in ways that may work to the detriment of their own constituents. Republicans in Congress also voted last month to allow the president to cancel funding for public broadcasting, including for stations that can be vital lifelines of communication in rural communities, many of them represented by the G.O.P.