FYI for those that didn't know, I was towing approx 6,000 pounds on a TRITON V8 Expedition, with torquetion control bars, and with sway bar. The back trailer had only swayed on one other occasion when a flat faced winnebago that was apparently traveling right behind me, I didn't see it. It went to pass me but put no distance between me and him. We came within 6 inches of colliding, but it did send the back trailer swaying. One tap to the brakes settled it, however, I was on flat stretch of I-10 near pensacola and it did sway about 4 to 6 times before it settled down at roughly 35 degrees of sway. The travel trailer seemed unaffected during this event, however, in the wreck event, the travel trailer did seem to be affected prior to the roll.