A thought on bridges collapsing

Given the tragedy yesterday and all the discussion about it, I just thought that I would look up the number of major bridges in the US. One source, even if the source is of questionable reliability, puts the number at 467. (I didn't count all the covered bridges, though there certainly seems like a lot of those. I also only did one faset count so that I might be off by a couple.) In any case, I think that it has been something like 17 years since the last bridge collapse. 1/(467*17)= 1/7939 is the rate per year that a major bridge collapses. I guess that the rate is a little higher than I would have thought, but the number hopefully gives one some perspective. If the list that I am using is incomplete, the rate of collapses will be lower than what I report.

I am not putting this up to minimize the tragedy, but to give some perspective. Especially since everyone is going to extrapolate from this into claiming that something needs to be done instantly across the entire country.