(0) a place where nobody else can have an SUV whose extra size directly increases the danger to your kids, but you also can't own one to keep your kids slightly safer while you drive them; or
(1) a place where you can have an SUV that keeps your family slightly safer while they're in it, but everyone else can also own one and they make your family less safe whenever they're not in an SUV themselves?
Social rules are, at least at their best, a way to do better than a Nash equilibrium of mutual defection.
(0) a place where nobody else can have an SUV whose extra size directly increases the danger to your kids, but you also can't own one to keep your kids slightly safer while you drive them; or
(1) a place where you can have an SUV that keeps your family slightly safer while they're in it, but everyone else can also own one and they make your family less safe whenever they're not in an SUV themselves?
Social rules are, at least at their best, a way to do better than a Nash equilibrium of mutual defection.