The man was shot at about 4:30 a.m. on eastbound I-80, Albany police said.
After the shooting, the man continued driving and went to his home in Richmond where he called police, Richmond police Sgt. Bisa French said.
He told relatives that he passed a white car while driving. He told them the driver, who was wearing a red cap, slowed down and they caught each other's eye. He said he didn't see a gun and did not know he had been shot. He said he felt a slight sting in his leg.
The victim had a bullet pass through one leg and land in the other.
The side of his car had several bullet holes.
Richmond police took the initial report and then called Albany police for assistance in determining where the shooting had happened, Albany police said.
The California Highway Patrol shut down the highway for a short time while police searched for shell casings, CHP Officer Ralph Caggiano said.
Richmond police initially told Albany police that they would be handling the investigation, Albany police said. But later, Richmond police handed the investigation over to Albany since the shooting appeared to have happened in that department's jurisdiction, Albany police said.
Bay City News contributed to this report. Albany police said this morning they were still waiting for Richmond to pass along the report from the initial investigation.