time2roll is correct and the change in the wording was to clarify the old definition that grammatically allowed some exemptions. At the same time the definition was expanded to include "ALL VEHICLES" with 3 or more axels, speed limit is 55.
I cannot defend this speed limit for towing nor with 3 or more axels in any way shape or form. The law actually came about from the AAA feeling that in their tests that were done long before I was born, that the mechanical and hydraulic brakes of the 20's and 30's were not capable of stopping within their opinion of a safe distance.
It is so hard to say without making yourself liable(morally) to some degree at least, that 60 or 70 is okay in CA as everyone does it and the CHP allows leeway.
I like going to 60 with the towed and I do. That speed is in my comfort zone. The difference in the handling of our Winnie(F53 chassis) and our former Bounder(Chevy P30) is remarkable and I have found myself cruising at speeds above 60mph. Then I consider what I know I am comfortable at while towing and slow back down. But that is for ME and how I feel. Even if CA were to go to the 75 mph limit for towing, you will find me in the far right through lane doing 60 mph.
I have looked at accident reviews on the highways for most states and we do not have lower accidents rates involving vehicles towing. Improvements in technology has lower the accidents per miles driven not the speed limit in CA.
I'm not bashing Florida, this is tongue in cheek, I've seen more single car accidents in Florida than any other state we driven through. I didn't look at that statistic in reviews by state, it was a one time observation.
It is time for the State Of California to grow up and admit they have some ridicules driving laws.
Now to give you my opinion why the fines are so steep in CA, we passed Prop 13 decades ago and for good reason. Extrapolation from the time of the passage of 13 to today, our property taxes would be well over $15,000 dollars a year instead of $1500 today and that is in 1970 dollars. At least that is what my CPA said to us when we had our taxes done this year. It is true that the politicians in CA today feel that the Federal Government should follow CA's guidelines for everything after all they are all knowing.
Okay, now my rant is over and I've in effect bashed CA after bashing you guys for doing it. Sorry! Please don't let our speed limits or politicians stop you from coming here to visit. We are as spectacular as any of the other states and well worth a visit.