Even though I do not like to drive at 70 mph in my DD or 60 in my MoHo, I think the CA Highway Patrol and our legislature have the collective heads up the behinds and in outlying areas like I-5 n/o Castaic where the truck speed should be 60 to 65.
There are areas in CA where 45 is too fast for us big guys and sadly I must admit my home town of Los Angeles has some of the worst drivers during rush hours(those are from 06:00am to +/- 09:00pm. It is not exclusive to L.A but all Big cities in CA.
With that said, if we turned our flashers on when the real time speed is less than 45mph, we would have them on all the time. But in the mountains and away from city traffic, 45 to 40 is when I turn mine on.
As far as me being a hazard driving in the far right lane at 55 to 60 in my rig in a 70 to 80 mile zone, I don't really see that. It is far safer than those drivers that feel 70 mph in the right lane is a God given right when the left lane is averaging 65mph.