They can't I don't think. For a patent it has to be a completely new idea, and my 79 Bronco and our Excursion both have easily removable rear seats to open up the cargo area.
I haven't personally run much much in the sand, so I can't say. But I've had good luck everywhere else just airing them down. I know my dad ran 9.00R16 tires for a lot of years and those will go almost anywhere with 20 psi in them.
Unfortunately since I put mine on I haven't had a chance to do...
I run Cooper 255/85R16s on my 79 Bronco and I like them. Haven't been in anything too nasty but they've done what I need. I've always been a believer in tall skinny tires anyway.
So both the states that I looked at (NE and KS) say that a secondary, MECHANICAL parking brake is required. Apparently it just can't be hydraulic, so an electronically actuated mechanical brake is fine? Unfortunate. I actually wish they truly required a mechanical one though, I don't think I'll...