The National Transportation Safety Board says a distracted pilot driver speaking on a hands-free cellular phone, inadequate clearance signage and a trucker unaware of lane rules share the blame for the span collapse of Washington's Skagit River bridge last year.
The state's automated oversize-load permitting system also needs updating, says the NTSB's report on the May 23, 2013, incident, in which a truck hauling an oversize load struck the Interstate 5 Skagit River bridge, causing a span to collapse 38 ft into the river.