What happens when a component fails on a bridge? What if the design of the bridge makes a single failure more likely to bring the entire structure down?
These questions could be asked after the collapse of a bridge on the Interstate-5 freeway in the State of Washington.
Jim Miller (who writes extensively about National politics, and somewhat about local politics) notes that regional authorities had a process for testing and licensing for carrying oversized loads across bridges.
He also links to an article which has a very useful diagram about the bridge failure.
I've copied the image below.