Are we considered "trucks" on the road?

In my state (Washington) if you're over 10,000 lbs you're a truck in the eyes of the law with regard to speed limits (and other things, like tire chain rules). The only big vehicles that do not have to abide by the truck speed limits are inter-city buses. I guess it helps to have good lobbyists in Olympia.

When towing you are subject to truck speed limits too (but nobody seems to obey them).