[inverba]

Unfortunately this is flawed in a very fundamental way. The NYC subways have different schedules for the morning rush, afternoon, afternoon rush, evening, and night. There should be at least three different distributions in the delay/wait data. Without teasing apart these distributions, I'm not convinced that anything meaningful can be said.

[maxaf]

The author did limit his "sunk cost" analysis to 7am-7pm due to this exact reason. I think that part at least is quite sound, and is probably the most enlightening takeaway.

[shockzzz]

It also doesn't take into account the distance between stops. The L train has a short route compared to other lines.