On: Ever-growing cars: why they keep on getting wider

[wcoenen]

I think the more relevant equation is a=𝚫v²/(2d) which gives you the acceleration needed to realize a speed change 𝚫v over a distance d. Larger cars allow for a larger d, therefore a smaller peak acceleration in crashes.

edit: I just realized you were focusing on mass. While a higher mass is safer for you, it comes at the cost of making things less safe for everyone else. Making cars larger while keeping mass the same doesn't come with this trade-off, it reduces peak acceleration for everyone.

[jakeogh → wcoenen]

To your edit: yes, that's what "The longer distance that big vehicles have between people and hard surfaces is a good thing" means.

Larger (modern) vehicles do weigh more; car density does not change much, I would be interested if there is a significant counter example.

[jakeogh → wcoenen]

Yes, max(a) is the thing to minimize, but to explain it I think starting with the F=ma symmetry is more intuitive, and then point out why d matters.