I’ve hauled potatoes. Top heavy,...not so bad. I’ve hauled liquid, now that can really rock and roll.
I’m guessing he got distracted (phone, sleepy, whatever) and realized, for that curve, he was going too fast, and too late to save it. It could have been worse if he had been in the oncoming lane and then laid it over. That guard rail could have flipped it on its top, and the truck would be trash. As it appears, that rig looks quite repairable.
My husband used to talk to a lot of the truckers going over Monteagle Mountain on the radio and they said hanging meat was the worst to flip a truck. It starts swinging in the truck and over they go. I don’t know if they even haul it like that anymore. It’s been a while.