This is a good article but I feel the headline is a bit misleading. Very few cities have actually adopted the 3-30-300 standard as a goal. Getting them to explicitly endorse it is the first step. I have suggested this in my city but no one had heard of it yet.

Unfortunately, here in the US, cities always seem to only copy one another rather than reach for the best practices across the world. We see this very obviously with street design but it’s also true with green infrastructure like trees.