If you don't want to do the carseat thing, I use the harness that has an attachment that hooks into the seatbelt lock. One end hooks just like our seat belts and the other end hooks to their harness. You can adjust the length. You can get them on ebay for about 10.00 I use these for my babies and they do just fine. They safer than being "free" in the car, yet have some room to move. Good luck!
