Maps are not just essential for knowing where you are on the road; they can also be the source for many great car games. Another plus to using map-based games is that you can teach your children map-reading and geography skills.
Give your children each a map and let them mark it up to help them keep track of where you are in your journey. Let them color, draw on it, highlight your route or use stickers to help them create their own personalized mementos of your road trip. As you pass different towns and landmarks, they can note them on their maps.
Older children can maximize their map-reading skills to figure out how many miles you have left until your next stop, and they can also calculate how long it might take to get there based on your speed.