The big-rig was westbound in the far right lane at about 3:30 am when it slammed into the side railing and went over, about 200 feet later the truck was smashed, its driver dead.
"We had multiple witnesses who stated that the driver was traveling at approximately 50 mph, the S-curve is a 40 mph zone, and when you are dealing with a large commercial vehicle, when you have a sudden shift of weight transfer, that is what caused the vehicle to go over the side of the Bay Bridge," said CHP Sgt. Trent Cross.
There was a mattress balanced on the upper deck of the Bay Bridge this morning. A CHP officer said it was the driver's mattress from the sleeping compartment of his rig. The driver's name is not being released, only that he is from Hayward.
Caltrans and the CHP said this accident, and the more than 40 others that have occurred since the S-curve was installed on Labor Day, are all the result of speeding drivers.
They are planning changes, for one more speed limit signs.
"We are also going to be putting up some reflective striping on the barrier itself, so that it is lit up at night. Also we are going to be putting in one of the radar feedback signs, the one that says 'Your Speed Is,' it will measure your speed and tells you how fast you are going," said Caltrans spokesperson Bob Haus.
The San Francisco Fire Department spread absorbent material at the scene to stop the fuel from the truck from spreading.
The semi was carrying a load of pears to an unknown destination.
Caltrans has not announced when all the changes on the S-curve will go into effect.
There was no structural damage to the bridge caused by the accident.