When familiarity is stripped away we seek recognisable signposts that will take us back to comfort and security. This is survival instinct. It is worth listening to as it keeps us alive.
Car travel for some pups can become a nightmare of hypersalivation and sickness.
Knowing your dog has receive sufficient preparation does not mean every eventuality, but a range of different conditions so that when the unexpected happens they will draw on their skills and solve the issue.