I've been living in a Northern Calif. area where nobody tailgates. On the other hand, they don't stop for pedestrians very much.
After many years I drove south to Los Angeles at 55 mph. I just couldn't understand all the people and truck drivers who don't understand that the right lane is the slow lane, and they appear to punish you for being there by sitting on your tail for a bit before almost knocking your tail light off passing you.
Why don't they join the other 65+ mph folks in the left lane(s)? I think they may become disoriented surrounded by traffic out there.
Then there are the ones waiting to take the next off-ramp.
If you have to stop suddenly I'm sure that many of them would rear-end you.
Any driver out there could blow a tire, hit the brakes, and swerve all over the freeway. I've seen it happen.
The truck drivers are supposed to be professionals but they were playing monkey see, monkey do on those roads.
I was a truck driver myself. My mission was to keep away from the cars.