All hazardous materials must be logged and any commercial carrier for hire has to be logged. This is according to Georgia DOT, different states different rules. Probably, I always thought if you where under 26,000lbs. you where good to go. Anybody else want to chime in on this. I would always check with your carrier requirements, as that is who is paying the bills! Normally a "C" unit is required to carry 5,000lbs. What you have for equipment is what will dictate your overall weight. blah, blah, blah... 14 foot box, seems to be the minium in most cases. This gives you a full 12 foot of storage, with your additional equipment on board.