The Congressional Budget Office has regularly published a report that documents trends in public spending for infrastructure. Here, CBO has updated the exhibits featured in that report through 2017. There are six types of transportation and water infrastructure that are paid for largely by the public sector: highways, mass transit and rail, aviation, water transportation, water resources, and water utilities. Federal, state, and local governments spent $441 billion on those types of infrastructure in 2017. That amount equaled about 2.3 percent of gross domestic product. The largest component of that total, $177 billion, went to highways, followed by water utilities and mass transit and rail.