A couple summers ago I drove the 5 from SD to Sacramento and the stretch in the middle, Bakersfield, Fresno, Modesto, etc, is literally Thunderdome. I drive fast in general, I have no problem doing 90 when traffic allows. The cars there on that stretch were tailgating me while doing 80 and flashing their high beams to get me to pull over, or they would pass around on the right side. Then there are the 18 wheelers strugling to go 60 which creates this inchworm slowdown that makes people go insane. Traffic was dense, but everyone wanted to go 90+. Cars on the right would pull up and close the gaps so that the cars on the left couldn't cut them off to pass cars on the left. Cars on the left would also pull up and close the gap so that no one could pull in front of them. It was the craziest, mass road rage induced scene I've ever seen and it was 5 hours straight like this.
I love CA freeways when traffic is moving because it moves fast, but that stretch of the 5 is insane. I take 99 now when I head North.