The big-rig struck a tree and jack-knifed on the ramp at about 9:20 a.m., California Highway Patrol Officer Kevin Bartlett said.
The driver of the big-rig, a man whose name is not yet being released, died at the scene, according to the Alameda County coroner's bureau.
The ramp was closed for three hours while authorities investigated and cleaned up the crash. It reopened at 12:20 p.m., Bartlett said.
