I have a problem with the seat belts. A friend lost her Airedale when she had an auto accident and it was directly related to the seat belt the dog was wearing.
I do try to use crates when I can. The problem (as Brenna's Mom mentioned) is that the crate won't fit into the back correctly, it barely fits at all. I'm used to having my mini-van where I could haul two crates (facing out) at a time. But I downsized to smaller vehicle and it just doesn't work with the crate. I even tried a soft-sided crate.
When I can, I put the dogs into the backseat, but there are situations when that will not work. For instance, the girls do not get along. When they both need to go to class, one has to ride in the backseat, but one has to ride in the cargo area. With the crate issue, it is difficult to keep the one girl in the backseat while bringing the other one out of the crate (at a slant and with the door facing the side of the car).
I see what you mean about the safety of the barrier not being a match for the crate (or seatbelt) though.
Thank you for sharing everyone.