Like humans, dogs can get carsick. Besides vomiting, signs of trouble may include inactivity, yawning, excessive drooling, whining, and smacking lips. This makes travel stressful for both the pet and the owner. There are ways to treat it, though.
The first way is conditioning. Get the dog used to the car and movement. First, just place them in the car without turning the engine on. Once they are fine with that, turn the engine on. Once they are used to the sound, try going on short drives until they are used to the movement.
Positioning can also make a difference. If you are using a crate, get one with mostly solid sides so the dog can’t look out the side windows. Looking out those can contribute to nausea. If they are wearing a seatbelt, have the dog sit in the middle seat and facing forward. The middle seat has less movement and staring out the front window reduces feelings of nausea. Also, having the window cracked can help with air pressure issues that can cause nausea.
Some dogs, though, might not respond to conditioning. For them, your veterinarian can prescribe medications ranging from anti-nausea to sedative pills.