All of my "research" revolved around my 35-40 pound Basset / Hound mutt. I might make different choices for different sized dogs.
IMO, the dog restraint is to protect my family, not the dog. I don't want him in a crate crashing into the back of a seat one of my kids is in or flying left to right if in their row in a harness.
My concerns:
- Standard crates and a vast majority of harness's will not withstand moderate crash forces. (I haven't found an in-store crate that I couldn't kick the side or door in if I wanted to.)
- Dog/crate or dog in a failed harness the impact into an occupied seat back could be devastating for the occupant.
- At least one harness in that study may lead to a horrible death for the dog.
- Gates that are designed to separate the way back from the back seat (like Subaru) are not going to withstand crash forces unless maybe they are bolted in and not pressure mounted.
With all of this in mind, I decide to use a Bergan for my dog in the front seat. It's connected to the seat belt where the lap belt anchors to the floor. That should hopefully keep him contained to the front passenger seat. I hope the airbag sensor works but we don't have a place in the back that doesn't put my kids at risk.
If DH is with us, the dog rides on the floor between my legs or on my lap. Sometimes I connect his harness to a seat leg, depending on the drive.
If I could fit all three kids into my second row, then behind the third row would be my first choice for him.
All that said, we recently took in a 100 pound Bernese. There really isn't a good way to transport him and the kids. He has some health problems so he doesn't go places with us. I just schedule his vet visits for when the older two are in school and drive extra alert.
ETA: I've shared this pic here before (it's old) but it shows the harness and where I connect it to the seat belt.