Visualizations : Status of U.S. Bridges by Year Built

From www.bts.gov: “Structurally deficient bridges are defined as those needing significant maintenance attention, rehabilitation, or replacement. Functionally obsolete bridges are defined as those that do not have the lane widths, shoulder widths, or vertical clearances adequate to serve traffic demand, or the bridge may not be able to handle occasional roadway flooding.”

In this view, it looks like, since 1997, the percentage of deficient bridges has kept steady at zero. This doesn’t seem possible.

Did the US Dept. of Transportation change the way they collect this kind of data? Or is this a glaring mistake in the data set?

The numbers in each time range are a count of the numbers of deficient bridges built in that time range. So this would mean that, so far, the U.S. doesn’t have any structurally deficient or functionally obsolete bridges built in the 1997-2002 range… yet! As those bridges age, I’d expect them to start becoming deficient or obsolete too…

When you look at all the states together, you can clearly see the effect of WWI and WWII in bridge construction.

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