As somebody who drives an ancient car, I'm keenly aware of its lack of safety features. The "american steel" argument falls flat; my car was made before the concept of crumple zones, much less airbags -- driving this boat, I'd be seriously injured or die in a head-on collison with a Yaris, where the other driver and passengers would probably walk away. Unless my gas tank explodes and engulfs us all, that is.
If everybody was driving pre-1984 vehicles, the emissions would result in horrible smog, bringing most cities on par with Beijing.
The world must bring carbon emissions down to prevent severe climate change. Maybe lax safety standards could contribute to that; but environmental regulations must not go.
Follow up: the "free" market that you propose is not actually free, but ignorant of externalities that the modern market has limited facilities to account for.
