i don't know whether this is considered car sick or not but zoey used to struggle a lot on my lap last time when i travel back to my home town every 2 weeks. it is a 2 hours ride home. and for almost an hour and a half of the journey she'll be struggling a lot. she doesn't want to sit on her own but wants to sit on my lap(she's a shih tzu). and for the remaining half hour she'll get tired and fall asleep. after a few months, she got used to it and will fall asleep once she gets into the car. she still insists on sitting on my lap though.