I just saw this. I guess, growing up in the country, I didn't realize that so many people did restrain their dogs. When I was growing up, we put the family dog in the back of the pick up and that was that. I wouldn't dare do that with my dogs now and in the city, but it's a lot different from what "city" people do for sure, even back then I'm assuming. My dogs never get crated in my car. I can't fit airline crates in it big enough for them, and quite frankly, I don't have the time or energy to keep moving crates in and out every day. Wire crates from what I hear don't work well in a car because they can break and puncture a dog, and I can't fit enough wire crates in my car of the right sizes for my dogs, either. Plus, I need to see out. I've tried harnesses; the dogs chew through them in the car if I go inside anywhere or it's a long drive and get tangled in each other to where they can't move. I'm 10x more distracted if my dog is in a harness, making sure they can move still and aren't tangled or chewing, than I am driving with them loose.
If my car were to go up in flames and I was knocked unconcious, I'd rather my dogs be running the streets/wilderness with tags and microchips than stuck dying in the back seat of my car.
That said, I've been in a few close call/almost accidents that were pretty scare and involved sudden stops, the dogs just roll off their seats onto the floorboard- I don't permit them to sit or stand, let alone move in the car. They lay down and stay there until we stop. Much better than rolling crates (which has happened before with fosters that I DID have to crate in the car) or not being able to see out of my car, imo.