HERCULES -- The California Highway Patrol has re-opened eastbound state Highway 4 in Hercules after a 28-foot truck trailer overturned in a fatal accident at the transition ramp from eastbound Interstate Highway 80 Thursday.

Two of the highway's three lanes were open by 4:04 p.m., according to the CHP.

The trailer truck struck the guardrail at the top of the left-hand turn as it began the descent on the transition ramp from eastbound Highway 80 to eastbound Highway 4 around 1 p.m., according to CHP Officer Scott Yox.

The driver braked and tried to correct his turn but ended up striking the guardrail a second time before the truck crashed, flipping the trailer onto its left side and blocking all lanes of traffic on Highway 4, Yox said.

The driver of the truck appears to be a 50-year-old man from Daly City, Yox said. The man was ejected from the truck during the crash and decapitated, according to Yox.

The cab of the truck and the sleeper berth were completely destroyed in the crash, but the trailer did not spill its load onto the roadway, Yox said. Shipping papers from the trailer say that the trailer is loaded with screws and bolts, he added.

A Sig-alert was issued at 1:13 p.m.