1. An FM transmitter to access Bluetooth capabilities in Bluetooth-less cars.
2. A pet seatbelt. Your pet's safety is just as important as any other passenger's.
3. A four-port charger that'll make you the lifesaver of the friend group. Think of all the times you wished your friends had a place for you to charge your phone in their cars.
4. A DVD player to provide all the entertainment you need on car trips... no matter how long the ride may be.
5. Red Bull, or any other energy drink you like. That being said, don't drive if you're *too* tired.
6. Sunglasses—so important to keep handy, because sun blindness is a real thing and can be so dangerous.
7. Hand sanitizer (especially useful after touching a germ-ridden gas pump).
8. A portable toilet. When you gotta go, you gotta go. Also, public restrooms kinda suck.
9. An essential oil spray to freshen up your car's smell (and to keep you feeling a little calmer while driving).
10. Wipes because kids are messy, you're messier when you eat behind the wheel, and these will save you from feeling yucky.
11. SNACKS. Sorry I yelled, but snacks are vital. How much does it suck when hunger strikes when you're in the car, and you don't want to spend money on food from the outside world? A lot.
12. Water bottles. You can never go wrong with keeping a case in the trunk for those moments when you just need to quench your thirst.
13. A trash bag—it'll come in handy when you're done with your snacks and water bottles.
14. A safety hammer in case you find yourself in an accident.
15. An essential oil diffuser that might just be able to make you feel like you're at a spa when you're really sitting in bumper-to-bumper traffic. Ok, not quite, but still.
16. Reusable grocery bags to help save the environment while you're shopping!
17. And a book outlining the best procedures for handling transportation-related incidents. It can't hurt to buy a copy and refer to it, should you ever find yourself in a dangerous situation.
Reviews have been edited for length and/or clarity.