I find Riley,s ezydog walking harness the best for car journeys, So easy to get into, a paw through the front, fastens over the neck , then under the back leg. It actually comes with a car attachment to fasten to seatbelt, but that doesnt give them much movement so I got the separate seatbelt attachment from amazon for about £5 and its brilliant, you can adjust how much movement you want the dog to have.