Here's a pretty remarkable chart showing the decline of public spending on construction (roads, bridges, public housing, sewage systems, etc.).
It shows total construction spending adjusted for inflation (we used the CPI).
It's fallen to its lowest levels since 2001.
construction spending
Another way to look at it as a share of GDP.
It's fallen far below previous lows on these charts.

(Thanks to Bill McBride for pointing out the decline in inflation adjusted construction spending)