No, per 100k cyclists per kilometre; that is, per 100k cyclist-kilometres, which is dimensionally correct. Or am I misunderstanding what it is you find weird?
I only glanced at the paper, but my suspicion is that they are using something like 100K cyclists per kilometre of road, not per kilometre actually cycled. They admit to not knowing the miles cycled, but if you guesstimate the number of cyclists and you know the length of roads in London, you can produce a "cyclists per kilometre of road" metric. I am not sure how meaningful it is.
On ChrisHallquist's post extolling the virtues of money, the top comment is Eliezer pointing out the lack of concrete examples. Can anyone think of any? This is not just hypothetical: if I think your suggestion is good, I will try it (and report back on how it went)
I care about health, improving personal skills (particularly: programming, writing, people skills), gaining respect (particularly at work), and entertainment (these days: primarily books and computer games). If you think I should care about something else, feel free to suggest it.
I am early-twenties programmer living in San Francisco. In the interest of getting advice useful to more than one person, I'll omit further personal details.
Budget: $50/day
If your idea requires significant ongoing time commitment, that is a major negative.