I went to the Prevost Prouds and FMCA & read both articles. The size chart is likely correct, as far as it goes.
In other words states do have the right to control length, on non federal roads. Thing is, most states have a large system of Federal roads where this chart does not apply. FYI, the reason most control length is to keep truckers from dodging interstate scale houses by ducking down back roads. The one that bothers me is the PP that got a ticket on I-10 which is clearly a Federal highway. I have personally driven this stretch with a 379 Pete pulling a
48' Van for a combined lenth of 74'. No problem. And you're right, Toy Box. With a 53' trailer, (the most popular size on the road today), a typical long nose sleeper truck would be 79' long. The only way I can figure California could control length on the Fed system is by passing a law specifically aimed at RV's since they are not commercial vehicles. OR, the folks that get the tickets don't fight them.