More than 10 percent of our nation's bridges are structurally deficient and in need of rehabilitation or replacement.

Of the 607,380 bridges listed in the federal National Bridge Inventory, 65,605 bridges are structurally deficient and more than 20,000 bridges are "fracture critical" and could collapse if a single component fails. Approximately 7,795 bridges fall into both categories, with more than 400 in New York state alone and another 200 in Illinois.

The Brooklyn Bridge and the Frederick Douglass Memorial Bridge in DC fall into both categories, considered to be a "red flag" category.

The problem is that many of America's bridges were designed for lighter vehicles and a lower volume of traffic.

"The physics is that they could fall at a moment's notice, or next month or next year — if they're left in the current condition," Barry LePatner, author of the book "Too Big to Fall: America's Failing Infrastructure and the Way Forward," told the Associated Press. "It's a ticking time bomb."

[image via AP]