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.



Anonymous Anonymous said...

The juxtaposition of events has always led to history's most interesting moments. A bridge falls down; a Senator who steered funds to a 'bridge to nowhere' is under investigation. And the third event will be...

8/03/2007 9:49 AM  
Blogger Almtnman said...

This bridge incident brings out two points, two not so good as it looks like all those pork projects was a waste when our infrastructure is getting way behind on maintenance. And people were killed when the bridge collapsed. The good point is, it has brought attention to all the states to take a look at bridges and see if they need work or rebuilding before another incident happens. I was surprised to find that my state has quite a number of structurally deficient bridges, some that I drive across and after this tragedy happened, steps are now in progress to correct them.

8/05/2007 9:02 AM  
Blogger John said...

John, I do not know what the definition used for a bridge collapse. During Katrina the Interstate Highway 10 bridge and the Route 11 bridge over Lake Pontchartrain both had parts fall in the lake. Also the Highway 90 bridge between Bay saint Louis MS and Pass Christian MS collapsed. Their may have been others also. If you include these it does make the numbers worse.

4/(467*2) = 1/233.5

John Leggett

8/05/2007 9:30 AM  

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