Always in a harness. Purchased intentional pet teathers that attach to the seatbelt bar.

Side note "squirrel"... FL passed a law that drivers cannot be distracted by pets and some counties require that dogs must be teathered in vehicles. For car I bought teathers that clip into seatbelts. They can be used in most golf cart seatbelts too I would think. I never tried them in my cart as I have two sets.