Long before they ever get to the point they need to be taken out from the standpoint of a structural deficiency, they end up being replaced because of a functional deficiency.

There has been no deterioration. It doesn't affect the structural condition of the deck. It could use some maintenance, but structurally everything's still looking good.

These bridges are safe to use. The issue becomes, you have so much traffic using them, they may suffer from a safety standpoint of having so many vehicles, and more accidents because you're cramming so many people through a bottleneck. We would never let a bridge that gets into a condition of having failure remain open.