The Congressional Budget Office regularly documents trends in public spending for transportation and water infrastructure. There are six types of 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.