I feel like adding a bit of local perspective (as I doubt the national news delved beyond the surface). The current story is that the truck would have been able to cross the bridge if it was in the middle of the of the two lanes (note that only the first span of the bridge collapsed the rest were intact). It has currently been alleged (by an eye witness) that another semi-truck failed to yield to the over-sized load, causing that truck to move to the right where a portion of the load contacted the frame. Also, the bridge was functionally obsolete because it was not capable of taking a direct hit to a load bearing girder. Modern bridges don't have that issue.
I'm no engineer, just a dirty ole Ironworker, but I bet that's the situation.
And I'm not trying to excuse the truck driver, just saying it was an antiquated design if I'm guessing right.
OK, I found this in a search:
link: Truck firm says it had permit to cross bridge that collapsed into Skagit RiverMike Allende, a state DOT spokesman, confirmed the truck had its permit.
"We're still trying to figure out why it hit the bridge," he said. "It's ultimately up to the trucking company to figure out whether it can get through. It's their responsibility to make sure the load they have can travel on that route."
WSDOT - Permit Types and Applications
Once you have submitted your rout with your application and fees, and the State DOT office approved you and give you the permit, that's it. You cannot deviate from the rout you submitted without extenuating circumstances. You cannot just change your rout on the fly because you wana. The DOT has to approve it (not all roads are designed for heavy trucks, and your alternate rout goes through areas which would have had roads rated for light cars, not heavy hauls. Additionally, large trucks are banned from many commercial areas not only due to weight but risk of colliding with a passenger car while executing a turn ), which means more paperwork, fees and time.
In many cases the driver and company have no choice, the DOT office will tell you what rout you have to take, and that's the only rout you are allowed to travel on. This is especially true for hazardous materials.
I suspect no one thought there would be a problem if large loads crossed this bridge regularly. Only when another vehicle failed to yield the right of way and the load struck a load-bearing girder was there a problem.
Last edited by Jerry; 05-24-13 at 11:35 PM.