Please Suggest Precautions to avoid kids vomiting in road journey

We are planning for a 6 hrs road trip(involves many hair pin cuts in the hill area)...I am just wondering is there any precautions to avoid my kid vomiting?

As she eat snacks and drink juice which don't get digest easily and that too when the roads are up and down, she vomits everything...

Will lemon help for kids?If so how do you use it..

Also please share your knowledge for elders also(me too have motion sickness)
Appreciate your response...

Thanks