Now you're getting into the philosophy of names and labels. Does a label follow an objects form or function or neither? Does it's use simply follow from the convenience of relaying an idea through the limitations of language?
In your example, does the label change if the human is not fat? Or if they are going to the bar instead of work? What is really pertaining to the nature of using the label "car" in your example?
In Switzerland we have Sand-Strips every so often for exactly that reason. If a Truck loses its Breaks it can drive into these Sand-Strips and it will safely and "gently" be stopped.
I have no affiliation, but this seems like a good place to bring attention to "The Guardrail Guy" on YouTube. He calls out damaged and improperly-installed guardrails. I'm not implying a bad guardrail had anything yo do with this particular incident. Just bringing awareness to a good citizen.
Yeah if this is the guy I think it is he lost his daughter to a car accident that involved an improperly constructed guardrail. If it was properly constructed she would probably have lived.