The incident occurred near the Mount Vernon offramp Tuesday around 4 p.m.
Authorities said an incident between two vehicles on the eastbound 10 Freeway led to a driver in a Nissan sedan shooting at another driver in a Honda on the freeway, hitting him.
The man who was shot then rammed the Nissan, which swerved onto an embankment. The driver who had been shot stopped his Honda on the freeway and got out and the two men started fighting.
At one point the man who had been shot then stabbed the other driver, police said.
Both men were taken to a nearby hospital and at least one had what were described as possible life-threatening injuries.
As authorities investigated, the Nissan was seen on an embankment along the freeway exit, its wipers still running. The Honda had extensive front-end damage and was towed from the scene.