it's a common term used around here because it is sadly, not so uncommon. People know the roads are dangerous but don't take precautions. I think it is a cultural thing where westerners perhaps humanize their pets a bit more than locals do. It's tough for me to understand how that can be but perhaps to them it is difficult for them to understand why we treat our dogs like humans. I don't really know. I don't know any Vietnamese people that have an "inside dog" though.