The best way would be to get blinds for the windows..lol not legal and ask the driver to drive on the best roads and keep speeds constant,,
I am guessing though that this isn't possible as it is out of your control, not to mention partly illegal
So the only real solution is simple stay awake for far longer than usual so that you are already exhausted before you set off trust me you will sleep..that is.If you currently have enough hours in which to stay awake now
I keep a Black Toque handy in My bag and a bottle of Z Quill . Take a capful of the Z Quill and pull the Toque down over Your eyes and You'll wake up 8-9 hrs later . A nice soft Blanket and some warm Slippers also come in handy .
Make sure you have plenty of leg room to be able to stretch them out when needed, many pillows that are comfort to rest your butt and back, neck in upright position. And don't forget to purchased black shades to keep the sun out of your eyes.
Tie a T shirt around you head to block out the light. sleep on the opposite side of the sun. lay down if you can. Pillow might help.
Fifth of Bald Knob Kentucky Whiskey Bourbon.
Stop twice to retch or vomit and you're asleep.
I usually lean on the shoulder seat belt and close my eyes
have someone punch you until you get knocked out
tylenol pm