MOUNT VERNON, Wash. - The Washington State Patrol chief says the Interstate 5 bridge collapse into the Skagit (SKA'-jiht) River at Mount Vernon was caused by an oversize truck.
Chief John Batiste told an overnight news conference that the truck hit an overhead span. The truck made it off the bridge and the driver remained at the scene and cooperated with investigators.
PHOTOS | Rescue efforts in Washington bridge collapse http://bit.ly/ZhtDQ7
Two other vehicles went into the water Thursday evening as the bridge collapsed. Three people were rescued and are recovering.
Officials said drivers should expect delays at the break in the major north-south highway about 60 miles north of Seattle. Detours have been set up to try to ease the congestion.
RAW VIDEO | Over the scene of bridge collapse http://bit.ly/13P0LdZ
The bridge was built in 1955 and has a sufficiency rating of 57.4 out of 100, according to federal records. That is well below the statewide average rating of 80, according to an Associated Press analysis of federal data, but 759 bridges in the state have a lower sufficiency score.