My daughter is 3 yrs old now. In past 6 months we have gone for 2 long drives with her. Once it was a 7 hrs drive and the next time about 12 hrs. And both the time she has been vomiting during the trip. Though we did take small breaks in between. What could be the cause behind vomiting and what precautions I can take the next time we plan to go for a long drive.
I have travel sickness till now. What works for me is lemon juice you can try this with your child.
Since your daughter is 3 years old I think you can give an antihistamine to her half an hour before you are supposed to travel. This should work.
May be she is not used to being confined to a small space for a long duration. Sometimes that also causes nausea and vomiting.