A good tiedown is essential. I once drove back (2.5h drive) from an event where I had lots of random stuff to haul back to the town. Being really OCD about cargo tiedown I had loaded everything like a perfect Tetris stack. The back of my 2006 TC was two thirds full of sporting goods, printers, dishes, coffee machine etc. So I was driving through the forest in the middle of the night, tired as hell after the event having worked 30h in a row an elk couple ran over the road. They were far enough but I instinctively braked as hard as I could. Could not hear even a drinking glass move in the back. Complete silence. I congratulated myself and kept driving.