[rocqua]

Being in a bigger car than everyone else makes you safer, but that gets largely nullified if everyone is in a bigger car.

That leads to an arms race with no benefit to anyone and massive costs. A prime example of when government should step in.

[wyager]

> but that gets largely nullified if everyone is in a bigger car.

This is not true - the collision between two large vehicles is safer than the collision between two small vehicles.

If you are colliding at a given speed, you want as much crumple zone between you and the other mass as possible.

> That leads to an arms race with no benefit to anyone and massive costs.

It has safety benefits to everyone. As for other net costs, consumers seem to think that (after factoring in emissions regs-induced distortions), large vehicles are net better.