I agree it's sort of grating and trite to hear these articles throwing out some random numbers chosen from a bell curve for their journalistic impact and then t

I agree it's sort of grating and trite to hear these articles throwing out some random numbers chosen from a bell curve for their journalistic impact and then touted abstractly. However, I've also just got back from living three years in London, and compared to living in 3 American cities and one Brazilian city, I can tell you the difference of living in a truly pedestrian friendly city with solid multi-modal transport options leads to a lot more walking, and I felt the health benefits of this. Even considering that I cycle commuted in all of the aforementioned cities, just the convenience of not needing a car (nor uber or taxis for that matter) led to a lot more walking above and beyond my natural recreational activity which I would find a way to do anywhere I lived. It's hard to quantify, but it's very very real. In the US there are very few places where you can live and not feel severely restricted without a car—you can do it in New York, and you can sort of get away with it in SF (although a lot of people's lifestyles would collapse if they had to give up their Uber and Lyft to instead rely on Muni)—but most places metros are tiny or non-existent, and buses are primarily used by the poor and have terrible service. There's no doubt in my mind that this has huge impacts on public health, but of course it's impossible to isolate the effect and quantify it since countries that do these things differently have all sorts of confounding cultural differences.