Business Insider's Henry Blodget recently wrote on the need for infrastructure spending in the United States.

Something that drives that point home is how badly some of our essential infrastructure has decayed. As of last year, 11.5 percent of US bridges, crossed by an average of 282,672,680 vehicles daily, were graded as "structurally deficient" by the Federal Highway Administration (FHWA).

The National Bridge Inventory is used by the FHWA to create a list of eligible projects for the federal Highway Bridge Replacement and Rehabilitation Program. According to the FHWA "HBRRP funds can only be used to replace or to rehabilitate bridges which are significantly important and are unsafe."

Bridges with a sufficiency rating of 80 percent or less that have not been built or significantly repaired within the last 10 years are considered "structurally deficient" and appear on the list.

From the FHWA's guidance on the program: "Those bridges appearing on the list with a sufficiency rating of less than 50.0 will be eligible for replacement or rehabilitation while those with a sufficiency rating of 80.0 or less will be eligible for rehabilitation."

Private construction is way up, but reduced public spending is a drag on the economy.

When we have 8.2 percent unemployment, historically low borrowing rates, and a stagnant recovery, we need to be fixing this and building better infrastructure for the future. Here's somewhere we can start.

Note on terminology: A sufficiency rating is a measure of a bridge's sufficiency to stay in service based on four separate factors. A deck is the bridge's supporting surface, the superstructure supports the deck, and the substructure is the bridge's foundation. Each of the following bridges is on the FHA's list, and has a sufficiency rating below 80, which is the threshold below which a bridge is considered deficient.