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Comment by rayiner | Hacker News Reader

> You think DC should be running the risk of accidents which kill riders because of trains that lurch into stations?

DOT estimates the cost of a human life at about $6 million. Times 9 is $54 million. Let's say such an event happens once every 10 years, so $5.4 million per year. The D.C. metro has 180 million rides per year. That works out to 3 cents per ride. Do you think people would pay 3 cents for a smoother, ATO-controlled Metro ride? I bet they would. (That's not even counting all the delays caused be forgoing automated control.)

As to the switches and sensors--Metro already replaced the track circuits (per the NTSB's recommendation): https://wamu.org/story/17/04/06/metro-shelves-plans-bring-ba....

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It's worth elaborating on a central point; the idea that 'preventable deaths are unacceptable' only makes sense at ordinary human scales. In someone's day-to-day life, they aren't reasonably going to be in a situation where letting someone die will be the best alternative.

The situation changes completely at the level of the decision makers of countries and large cities work at. /Everything/ is a variant of the trolley problem and all resources could in theory be used to save a life. Not accepting a risk of death can do more harm than good and realistically infrastructure; it just obscures the cause and effect.

Eg, we'll never know if someone died because their doctor was late because a train operator made a mistake operating a train. The cause-effect chain is too convoluted. But statistically speaking, something like that will happen every so often. Deaths from inefficiency are just as bad as deaths from direct accident; and if the scale is large enough that they can reasonably be detected then they need to be considered too.

Obviously most of the time a high standard of safety is going to be best, but trains are a high-risk environment moving 100s people at speeds they were never meant to move. True perfection over 30 years is probably not a required standard. Great goal though.

This has been interesting to chew on. Let me say that if there are actually delays, obviously those impose other costs (as a sister post explains here) and so the cost-benefit calculation may come out differently. But your original post was only about whether it's worth risking lives to avoid lurching trains, which is why I thought it was interesting.

I think the problem with your cost-benefit analysis is that you are using different methodologies to value the cost and the benefit. If you value the benefit of non-lurching trains by asking what people would pay, then you need to use a value for human life that asks what people would agree to receive to be killed--which I believe is much more than $6 million.

Conversely, if you are going to value a human life based on lost earnings/support to family/etc., or some other figure which might produce results in the ballpark of $6 million, then on the other side you need to consider only the lost earnings/hard economic costs of an annoying train ride, which are $0 -- there is no economic loss caused by lurching into a station.

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