A portion of the highway is closed in both directions.
CHP says an officer responded to the scene east of Highway 99 near Merle Haggard Drive, just after noon on Friday.
There was a crash, involving a white pickup truck. An officer says when he arrived he saw a man running around in the area with a weapon.
A short time later, the officer fired his weapon. There is no word yet on why he fired his weapon.
There is no word on the condition of the person who was shot.
Officials say the pickup truck hit a power pole. A downed power line is forcing detours that could be in effect for several more hours.