I think it was a combination of factors that led to this wreck. The BIGGEST factor was inexperience! If not, the other factors wouldn't have come together and culminated in this wreck.
The WDH (not sway bars) can induce sway if not adjusted equally. I have noticed my trailer not towing 'right', stopped and inspected to find it was 2 links different and readjusted it and started back on the highway to a trailer towing like it should. This was when I was towing with my 1500 GMC and over capacity. I had another incident also - while on uneven terrain and turning, I had the head platform of my Reece 1,200 lb trunion style WDH "blow" out. One side would not stay hooked up and I had to tow 90 miles back home like that. A new head platform ($130 later) fixed that. Reduced speed and the friction sway controller helped me get home safe. Depending on the trailer weight, length, axle placement, and the size of the tow vehicle, its capacities, and how close or far from them your rig is, weight distribution hitches can be used with only 1 bar and sway may not be noticed. BUT having a bar pulling down on only 1 side of a trailer does have an effect. It may be more noticable on some trailers than others.
The WDH in the pics are of round bar design (usally 800 lb bars). They are inserted from the bottom and locked to the hitch head. One side is completly off the hitch - either it wasn't properly attatched or ripped out. I go with not properly attatched.
The friction bar (anti sway control) isn't hooked up nor does the ball look as though one had been used at all. It would have helped. I recently replaced one that had become ineffective due to age and weather, and boy can I tell a difference, EVEN WITH my new 2500 truck!
Trailer brakes are another factor. Either 'lack of' OR improperly adjusted brakes contributed here. On wet roads, trailer brakes can lock up and jackknife a trailer. Proper adjustment and use of trailer brakes can add a whole new level of brakeing safely. If sway had started, light to moderate, and even intermittant application of the trailer brakes can reduce sway. Once sway has started, using the TV brakes too hard adds to the bad situation. LACK of trailer brakes can cause wrecks too.
Experience would have had the driver check his rig and also adjusted it for conditions. He/she would have had a friction sway bar attatched too.
Bob and sometimes - Nina - a Staffordshire Terrier/a SPOILED pit and her kitty Spaz
2006 Dodge SLT 2500 4x4 Cummins Quad Cab w/AT and 3.73
2007 Salem Sport LE 26FBSRV (TH) w/ my Victory Motorcycle in it or a EZ GO Shuttle cart.