[dfxm12]

...This included 61% of young people aged 18-25 and 51% of mothers with young children.

Going from college, surrounded by people looking to socialize, to who-knows-what, is quite a transition. I bought my house near public transit options and within walking distance of entertainment/recreation options on purpose. I know that's not always easy to find, but like you say, a significant part of this is a policy choice, not just because of public transportation, but zoning could play a part in it as well. The city I live in has since given grants to businesses building along public transit routes and it is having a positive effect on people being out and about.