> I do not like this math Many policy difficulties arise from unwillingness to trade-offs between "sacred" and non-"sacred" values. It's easy to say that just

> I do not like this math Many policy difficulties arise from unwillingness to trade-offs between "sacred" and non-"sacred" values. It's easy to say that just one life is worth an arbitrary amount of non-fatal inconvenience to an arbitrary number of people. It's the cheap, easy platitude anyone can summon in a meeting. It feels good to say. Simple. Strong. Righteous. But the world doesn't work this way. Mere life does not, in fact, have infinite, overriding value. Infrastructure engineering is not a morality play. It's a complex set of trade-offs, some involving safety. In a big system like public transit, as crass as it might be to say explicitly, the optimal number of deaths is seldom zero. Safety and utility are not, as the moralists might insist, incommensurable. They in fact exist on the same plane, and to build things that are effective and efficient, we need to trade them off against each other. Failure to do so leads to cowardly paralysis. In other words: yes, we absolutely should accept some statistical nonzero risk of injury to save time or money in the overwhelmingly common case, because these things matter.