This is the first story of our three-part series on the state's bridges.
If you drive in Pennsylvania, you've probably crossed a structurally deficient bridge. Maybe you're driving over one right now.
Pennsylvania has more than 30,000 bridges. Some span rivers, like the Ben Franklin Bridge in Philadelphia, and others are much smaller, crossing rural creeks and highways. More than 6,000 of these bridges are structurally deficient. (We put together an interactive map of the state's structurally deficient bridges.)
You might think that means the bridges are on the verge of collapse. Engineers say that's not the case.