I think the little animal with the hollow bones would be pretty screwed in a car accident in any case. They're not wearing a seatbelt so they're going to get flung against the sides of the carrier when the vehicle comes to a traumatic stop. A soft-sided carrier would be better than hitting something hard, but anything will do some damage if you hit it hard enough.

In some ways a harness is like a seatbelt, but it's not going to function that way unless you've got the leash cinched up so short that they can't travel more than about half an inch.

You can wear it as a baby carrier or carry like regular xarrier. Has spot in back 4 seatbelt too.