Here in Oklahoma I've seen the OCC (our DOT cops) pull over a 1 ton with firewood on a trailer. They're cracking down on lighter trucks that need DOT numbers, logs, medical card etc. even if they're too light to require a CDL. Pretty much anything with dual rear wheels, especially with a trailer is rated over 10K so there you go. The only way out of it is to be a farmer or register it as an RV. It's pretty hard to prove you're not using a truck for some form of commerce. A lot of oilfield companies around here are downgrading from one tons to three quarter tons so their mechanics, pumpers etc. don't have to meet DOT criteria.
