I just searched Arizona law and they do not define "Passenger Carrying Vehicle." I'm wondering if what they intended to mean by "Passenger Carrying Vehicle" is a vehicle that carries passengers for hire? If so, they don't appear to define it anyplace, so by literal reading of that statute it would mean any vehicle capable of carrying more than one person. That is assuming the driver isn't defined as a passenger.
I've worked with California laws for a long time and they are just as confusing as any others, but California is generally pretty thorough in defining everything as long as you know how to look up those definitions. For example California law calls a motorhome a Housecar. Under the definition of housecar it tells you exactly what it is. And as you the read the various laws in the vehicle code it tells you if Housecars are exempt.