Please explain that line of logic. Private - not for hire - noncommercial can and probably would still apply.
at least, here in NY, private/non-comm does not have to stop for anything DOT related. i just went through this, as i am registering a 1988 mack r model single axle tractor, in my name. (non-business, for private use only). the only thing commercial on the truck is a commercial plate, just like a pickup. i have been in person to the DOT building in albany, and sat down with the appropriete people to be sure i am doing things right. i was handed only one peice of paper to keep with me; it says that non-comm/private vehicles do not have to stop at dot checks, and dot numbers are optional in my case. i was told if there was any problem, just hand this paper to the authorities, as it spells out the guidelines, and is on DOT letterhead. i have been in heavy equipment trucking (large, overweight, overheight, overwidth, 150ton loads) as a driver for several years now, so i do know what i am doing, and have had more than a few run-ins with dot. the thing is that you cannot be doing anything that looks or is being done for money. this specifically includes, as i was told by dot, going to horseshows in an attempt to win ANYTHING, including ribbons, accessories, trophys, or $$. i am not saying i agree, but i was specifically told this in the meeting.
Air brakes do not require a CDL even in commercial use.
this is true in ny. my last employer had several freightliner/ih service trucks, that none of the drivers had cdls, yet they all had air brakes. no one was ever given a problem.