You know, I really wouldn't put it past Uber to game HackerNews. If they're willing to dig up dirt on journalists, can you imagine that they'd have a problem with 'employee advocacy' on HN?
12 years/mile. So, I see rate (1 mile) and time (12 years). If you want to REwrite this, you can say (1/12)mile/year.
And that's also a speed.