In the wake of the I-5 bridge collapse, the authorities want you to know that "structurally deficient" and "functionally obsolete" don't necessarily mean "about to fall into the river." It's true! They don't. Necessarily. The Skagit River Bridge combined two problem categories: It was functionally obsolete, meaning built to outdated specifications, and it was fracture-critical, meaning that if one key part fails, the whole thing fails. It's believed that that failure of one part was triggered when an oversized truck hit the bridge at the wrong place.
So what are the lessons we should be learning about American bridge infrastructure? There's no doubt it's hurting, with tens of thousands of structurally deficient bridges needing tens of billions of dollars in repairs. Public construction spending as a share of GDP is not a pretty picture right now:
There's a strategy question paired with the funding one. The story of the Skagit River Bridge makes you wonder if we shouldn't be focusing on replacing rather than repairing many bridges. This bridge has been repaired repeatedly in recent years. So, uh, why is the government spending a bunch of money repairing a bridge that doesn't meet modern traffic needs, will fall apart when hit by a truck that apparently did not sustain all that much damage, and was at one point structurally deficient? Repair is cheaper in the short term, but aside from the long-term costs that can be racked up, it leaves us with bridges that are too narrow or don't have enough clearance. Lots of such bridges, along with lots of actively unsafe bridges.
It's completely of a piece with the narrow thinking and refusal to invest in the future that has plagued our government in recent decades. But at moments like this, that lack of vision for the future should be part of the discussion.
