not meaningful at all
Paging Tony Stark! :-)
Cyclists per kilometre of road is a measure of cyclist density. To do a proper density estimate you also need to know how long (in hours) does an average cyclist spend on the road, but conceivably you can handwave it away as a near-constant. Given this, their approach is to look at the fatalities as a function of the cyclist density.
They are still missing too many variables to produce a useful estimate, but it's not prima facie insane.
Yes it is prima facie insane, because the number of fatalities should look like f(density) times quantity of road (or quantity of cycling or something). Maybe they kinda get away with it when comparing fatalities across years, because the quantity of road doesn't change much -- but that would equally justify measuring quantity of cycling as, say, "number of cyclists divided by latitude" or "number of cyclist-kilometres times number of letters in city name". So, good try, but I still think it's obviously bonkers.
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.