Per past threads in an engineering forum http://www.eng-tips.com/threadminder.cfm?pid=607 I regularly read, gusset plate/steel girder bridges (the one that collapsed) and including the Minnesota I-35 bridge that collapsed a few years ago have a number of vulnerabilities and some have had design flaws that have gone for years undetected...

The above engineering forum in time will likely have some hard data posted on the failure..

While a vehicle strike (a predictable possibility) is being cited as the cause, it will be interesting to see if the bridge already had other issues that allowed the strike to escalate to failure..

http://www.nytimes.com/2008/01/16/washington/16bridge.html?_r=0

https://www.google.com/search?hl=en&...&as_rights=

and nobody wants to pay (taxes) for replacing/repairing aging infrastructure.