Heading off on a road trip is a whole new experience. For some, it's extremely tiring. For others, the new air and the germs from the highway gas stations prove too much for their immune system to handle. Because of this, many people find themselves feeling run-down or ill during a road trip. To prepare yourself for this possibility, you might want to pack some vitamin C supplements in your bags.
If you can, buy fresh oranges and citrus fruits. But if you can't, you could stock up on vitamins, liquid IVs, or tablets instead. This should ultimately perk you up.