Bryson was driving a Lexus in the 400 block of South San Gabriel Boulevard on Sunday evening, when he allegedly rear-ended a Buick as it was waiting for a train to pass, according to a statement issued by the Los Angeles county sheriff's department and the San Gabriel police department.
'Preliminary investigation indicates the collision was caused by suspect John Bryson, who is the United States secretary of commerce,' the joint statement said.
Bryson, 68, was found unconscious in his vehicle and has been hospitalised, officials said.
After briefly stopping to talk to the three men inside the Buick, Bryson left the location in the Lexus and then struck the Buick a second time, authorities said.
The men followed Bryson's car and called 911 to ask for police assistance.
Bryson continued to drive his Lexus into Rosemead, which is patrolled by the Los Angeles county sheriff's department. There, he allegedly crashed into a second vehicle near the intersection of San Gabriel Boulevard and Hellman Avenue.
There authorities found him alone and unconscious behind the wheel of his car, the Los Angeles Times reported.
Bryson was treated at the scene by Los Angeles county firefighters. Authorities said drugs or alcohol do not appear to have played a role in the crash. They said Bryson was cooperative.
He was cited for felony hit and run but was not booked into jail because he had been admitted to the hospital. His condition was not known, the report said.
There were no serious injuries to the passengers in the Buick and Honda. Bryson's Lexus and the Honda suffered minor damage, the police said.
Bryson, who took office last October as America's top commerce official, was the chairman of Edison International. He had helped Edison International emerge as a leading solar and wind power firm.
There was no immediate response for comment from the commerce department, US media said.