One of my other poodles had a problem with this. She could just about make an hour's ride in the car but no further. We could tell when her limit was about up because she would start to drool. When we first got Bella I was originally a little worried too. On the way home from the breeder's she was fine and slept in my daughter's lap the whole way, but on her first couple of trips to the vet she would drool in the car. I thought, oh no, she's probably got motion sickness. Gradually I noticed that instead of standing up in the car, watching where we were going, she starting laying down. It seems that when she lays down there is no drooling, so I think the potential tummy upset might have been in watching things moving by. Now when we get into the car she immediately lays down so I think she just realizes in her own way that she feels better this way. Maybe if you could sort of force Kersey into a laying down position when riding it might help? I don't know, but can dogs outgrow this? I guess your vet will be able to give you the official answers on this one. Good luck!