The truck drifted off 99 slamming into some barrels full of sand protecting the concrete pillar of a pedestrian bridge over the connector.
The driver was found dead in the cab of the truck after the crash but it's not yet clear if he was killed by the crash or died before the crash.
Another driver asleep in the back of the truck's cab was not seriously hurt.
Sand spilled across multiple lanes of the highway from the force of the crash. The truck's fuel tank was punctured, spilling diesel onto the roadway.
The connector ramp was closed for a few hours while the Highway Patrol investigated and Caltrans cleaned up the spill.