I often get carsick riding in the back of a car. As an adult you don't really notice it as much since driving kind of forces you to focus on the horizon. As a kid someone gave me a hack for not getting sick when i rode a bus or car.
He told to imagine a ninja running alongside the car. With an active imagination it is possible to do it automatically every single time you get into a car. The game pauses whenever you get off and resumes as soon as the car starts again. Not every child can mentain such a level of imagination for long without getting bored, so why not make the imagination real?
Making a game where a person runs alongside the car level to the horizon and the objective is to miss obstacles. such a game could be really helpful to kids or anyone with severe motion sickness. It also doubles as a form of entertainment for those long trips.