I wish this organization would be more precise with their wording. It isn't really the harness that is of concern, although some harness designs hold a dog better than others and are probably less likely to cause injury in an accident. If the harness you use is good for walking and inescapable, it will likely be safe in the car accident.
The issue is the tether, the thing that secures the harness to the car. If it is too long, the dog can be thrown too far. If it is not sturdy, it will break on impact.
If I can swing my dogs on their leashes without the clip breaking, I wonder if the clip on a car seat tether would break on impact. That is the question.
__________________ Kristin, Max and Teddy |