Olives and pickles! Those are kind of hard to over-indulge in, I think. Maybe take a small baggie of sunflower seeds, too? Something already portioned out so you can eat too many. As much as I think it’s important to break bad habits, I also think it needs to be done in moderation when possible.
I completely understand wanting to snack while driving. I’ve always said I couldn’t be a truck driver without weighing 400lbs. I might also suggest that, if you fast 1/2, you still have some planned snacks for when you break that fast. Otherwise, convenience store foods might be too tempting.
Be sure to take your water, too!