Wolf Blitzer To NTSB Spokesperson... How about signs... (I-5 Bridge Collapse)

[Spider Jerusalem]

13. I found a news story that says:

There were no signs leading up to the Skagit River bridge to warn about its clearance height. State Transportation Secretary Lynn Peterson said that under federal and state standards, the clearance is tall enough to not require signage.

For reference, the vertical clearance from roadway to steel beam was 14'6". Here's an overpass with seven inches more clearance that's still marked:



The state regulations for highway safety in Washington state may have different criteria; I also found a USDOT memo re vertical clearances on the Interstate Highway System which specify 4.9m (16 feet) vertical clearance, and the Washington State DOT also specifies 16 feet 6 inches (on new structures). Further, contradicting Ms Peterson's statement:

Low clearance warning signs are necessary when the vertical clearance of an existing bridge is less than 15 feet 3 inches. Refer to the Manual on Uniform Traffic Control Devices and the Traffic Manual for other requirements for low-clearance signing.

http://www.wsdot.wa.gov/publications/manuals/fulltext/M22-01/720.pdf