http://www.capradio.org/news/npr/story?storyid=301755828
All lanes of I-5 closed until further notice.
Traffic would have been detoured onto US 99W, albeit only a two-lane road.
I took a quick look at the Google Street View of the area. It amazes me that CalTrans does not even have a cable barrier in that area of I-5 that might have retarded the speed of the Fed-Ex truck crossing the median. There's nothing there but vegetation in a narrow median.