New Mexico.
For commercial it's far from ideal, short overall combined lengths etc., but for private use just about anything goes, it seems. Then there are no length limits on trailers, or how many you can pull.
Of course, with freedom comes responsibility, and it's cringe worthy to see many of the setups heading for the lake, for example. Boats and other stuff towed behind travel trailers.
Okay, not saying that can't be done correctly, but quite a few of the tow vehicles going by are 1/2-tons and SUVs, pulling way more than I'd ever attempt.
Blind faith in the J2807 ratings I suppose, and exceeding them by a bit can't hurt anything, right?