Amazon Best Sellers: Best Dog Car Harnesses Discover the best Dog Car Harnesses in Best Sellers. Find the top 100 most popular items in Amazon STRING(pet-supplies-store) Best Sellers. Best Dog Harness for Car Travel (2019) - The Dog Clinic Car harnesses are designed to keep your pup secure when travelling - but which is the safest? And which should be avoided? In this article, Richard Cross reviews four of the best dog harnesses for car travel to help you choose the right one for your pet.