Help me understand California Turnouts - Updated

Cmead has it right. If it's not marked, it's not a "real" turnout. However, in California, you can use the shoulder to allow others to pass if necessary. Though that's not a great idea anywhere near a city due to debris on the side of the road.

Also, "flow of traffic" doesn't mean much legally in California. If you're doing 55mph, you're fine. If you're going slower, then the 5 car rule applies.