Our dogs travel in wire crates. There are also safety belts made especially for dogs if you wanted to make your dog is safe in that way.
Some dogs tend to get car sick. It is almost always caused by nerves. Over the years, we’ve had several dogs that tended to get car sick and what we’ve found in every single case was that the more they traveled, the less they got sick. When these same dogs that tended to get sick, make several short trips before a long one, there was less chance of sickness. We’ve gone on long trips with dogs prone to car-sickness on several occasions and the sickness is always confined to the first two to three hours of the trip and then they’d be totally fine even for trips that were 15 or 20 hour two day trips. Things that we’ve found to help were ginger, pheromone spray (put on a bandana and then worn by the dog), and in the worst cases a dramamine pill. Our dogs never travel on a full stomach (even those who aren’t prone to car sicknesses). We stop every 3 or 4 hours for potty breaks and walks.