This story was originally published by Inside Climate News and is reproduced here as part of the Climate Desk collaboration. Although the nation has seen record federal investment in infrastructure under President Joe Biden, the majority of the funds are flowing to roads and bridges—not to projects that will clean up the transportation system, those tracking the spending have found. In an effort to revive the original transformative vision that climate action advocates, including Biden, brought to Washington at the start of his administration, Congressional Democrats on Monday were set to introduce the Build Green Act, legislation that would invest $500 billion over the next 10 years in addressing the nation’s largest source of greenhouse gas pollution: transportation. The transportation sector now makes up 28 percent of US carbon emissions, and there has been little progress in reducing that burden.