The other thing with the Interstate 5 Skagit River bridge collapse, was the fact the oversize truck received the in - cab bypass signal @ Bow Hill scales. OOPS !!! I noted that the very next week, an electronic sign board appeared on S/B I-5 just before Bow Hill stating: " All oversize loads must exit to scales." This is standard policy with oversize loads in many states, including California, where all " Permit " loads must stop at every scale facility that is open. So yes, WSDOT shares some responsibility for this deal.
Still, the fact remains : The PILOT CAR DRIVERS did not do the ONE JOB they were hired to do!!! ( Making sure the truck did not hit anything with the oversize load.)
Yes, many states are not diligent about posting overhead heights under 14 feet on Interstate highways. Also, there are many state highways in the East and Midwest with older, lower bridges. I recall a truck trip with my Uncle Eddie from Scranton, PA., to The Battery in NYC in 1979. Even with only a 12'6" high dry van, we hit the ping pong ball overheight warnings at the Holland Tunnel. My uncle explained that the tunnel is actually 14' high, however the extra room is needed in case a truck breaks down and has to be towed out.