The Honolulu Medical Examiner’s Office identified the 47-year-old man who was struck Friday by a pickup truck on the H-3 freeway and later died.

Sam Nguyen of Honolulu was taken at 6:10 a.m. to the Queen’s Medical Center, where he died Friday afternoon. An autopsy will be performed Monday to determine the cause of death.

Police said Nguyen had been hit near Mokapu Boulevard on the H-3 freeway.

Nguyen was driving a 1993 Buick sedan in the northbound lanes toward the Marine Corps Base Hawaii when he lost control, crossed the grassy median and the southbound lanes and crashed in a wooded area off the highway.

Witnesses helped the man, who sat on a guardrail and waited for help to arrive.

Police said that for some unknown reason, Nguyen stood up and staggered into the southbound lanes and was hit by a pickup truck.

The 28-year-old male driver stopped to aid the man.

Speed, drugs and alcohol do not appear to be factors in the crash, police said.