Earlier quoted context omitted.
Drive the largest vehicle you can. When in a collision the momentum is converted to crushing force, you want to be in the less-crushable vehicle. Hey this may be an unpopular choice, but it is the one with the biggest safety impact! And that was the question.
I propose an alternative. Start including the effect on other cars in crash tests. In other words, yeah, if I drove a frickin' monster truck, yes, it's going to be extremely safe for me , but it's absolutely deadly to anybody in a sedan. So that monster truck should get low crash test scores. Your answer merely creates an arms race of larger and heavier cars.
Only if everyone can afford them, which isn't true. Its more like, creates a class system where the rich are safer. Which is already the case to be honest.