Now the Trump administration may rescind an Obama-era initiative that allows hiring preferences on transportation and construction projects in states like New York, California, Texas, Virginia and Illinois, a prospect that has alarmed advocates of such programs.

“Why not let cities and states innovate to create the good American jobs that the administration has been clamoring for?” said Madeline Janis, the executive director of Jobs to Move America, a coalition of faith, labor and other groups that want transportation funding to benefit local communities. “I don’t understand why they would want to cancel the program.”

Legal and regulatory hurdles have long frustrated officials trying to create job opportunities that favor local residents. The Supreme Court has ruled it is unconstitutional for employers in one state to discriminate against residents of another. Federal agencies, through Republican and Democratic administrations, have maintained that restrictions like competitive bidding prevent them from contributing a cent to public projects with hiring preferences. And state lawmakers, complaining that employers and workers outside the target city are at a disadvantage, have outlawed such preferences.

Jobs to Move America was one of several groups that spent years working with transportation officials in the Obama administration on a pilot project to test whether local hiring preferences reduced competition or drove up prices. In January, days before President Trump was sworn in, the Transportation Department extended the experiment, taking place in more than a dozen cities, for five years so that research could be completed.

In other areas, like education, Mr. Trump has chastised the federal government for imposing “its will on state and local governments.” This week, however, a Transportation Department spokesman said that “the prior administration’s proposed rule and proposed long-term extensions of pilot programs is under review.”