Four Trends in Infrastructure Spending

There is an interesting article from the Brookings Institute that documents four trends in infrastructure funding. The four conclusions of the report surprised me, and I suspect they will surprise others:

1. Infrastructure Spending is Up, But Spending as a Share of GDP is Down: The ratio of infrastructure spending to GDP shows the amount of national wealth that is reinvested in infrastructure. Seeing this ratio drop in recent years is an indication that, over time, the country is not reinvesting at the same level as in the past. Brookings says that most of the spending drop is related to highways, with the other categories of infrastructure spending the same or higher over time.
2. State and Local Governments Fund Most Infrastructure Spending: This is the finding that surprised me the most. To show the magnitude of the shift, in the 1970s, the federal government spent $1 trillion on infrastructure while State and local governments spent $2.2 trillion. In the 2010s, federal spending increased to $1.3 trillion while state and local spending more than doubled to $4.6 trillion. 
3. The Share of Infrastructure Spending on Maintenance is Climbing: The percentage of infrastructure spending on maintaining existing infrastructure is climbing, meaning the percentage of spending for new infrastructure is dropping. In the 1970s, 44 percent of infrastructure spending was to maintain assets like roads and buildings, and that has grown to 57 percent since 2020.
4. State And Local Revenues More Important than Federal Grants: State and local revenues are paying for an ever-increasing percentage of infrastructure spending. This means state and local taxes and user fees. Brookings speculates that increased federal grants drive State and local governments to fund more money than normal to use as grant matching funds.