Trend That Is Not A Trend: Crumbling Infrastructure
How many articles have you read on "American's Crumbling Infrastructure"? If you are like me, you are frequently left with the impression that deferred maintenance on infrastructure is increasing over time. As is often the case in the media, a trend is implied but no actual trend data is presented. Instead you will get scary single data points (e.g. 66,749 of the nation’s 607,380 bridges were structurally deficient).
It turns out, according to Chris Edwards at Cato, this is yet another implied trend that is not actually a trend. The data is easily available, but never makes it into the article
ErikTheRed:
That being said, their definition of "structural deficiency," combined with their accuracy and diligence in performing inspections means that any numbers presented are inherently suspect.
October 14, 2013, 2:49 pmJW:
Well, it *is* a trend, just not in the direction claimed by the media, going by that chart..
October 14, 2013, 5:43 pmDHL:
A more important question is whether the % of traffic at risk on deficient bridges is increasing or decreasing.
October 14, 2013, 7:17 pmMatthew Slyfield:
Another important question, how many of the structurally deficient bridges are deficient due to design flaws versus being structurally insufficient to to wear. Backspace?
October 14, 2013, 9:35 pmDouglas2:
In reply to some of the questions and implied questions below, "structurally deficient" as a term of art is distinct from "unsafe".
October 15, 2013, 6:32 amIf there is any indication that a bridge is unsafe, it is either closed or weight-restricted.
On the National Bridge inventory 10-point scale, anything 4 or below is structurally deficient. A 4 means, "we wouldn't build it that way now, but there is nothing otherwise wrong with it". 3 means "it would be handy to have higher weight limit/more clearance/sidewalk/etc., but no so much that we should budget anything". 2 means high priority for improvement, and anything less means the bridge is closed unless/until it is replaced.
DaveK:
Seismic standards that came into being in the 70's and 80's made a very large number of structures become "deficient" literally overnight. Many were just as strong as the day they were built. It has been a massive project to upgrade or replace these structures, and an amazing amount of progress has been made in the past 30 years. Of course, an amazing amount of money has been spent for this, some of which has been diverted from more mundane work like prompt filling of potholes.
October 15, 2013, 7:33 amnorse:
All true; I will say that whenever I came back from Switzerland, Germany or the larger Chinese cities, returning to the PNW felt like coming to a second world country. That might be entirely a local thing.
October 15, 2013, 4:06 pm