Mass transit enables people to live in low-density areas who otherwise could not. A massive proportion of the DC area population lives in the burbs, drives to

Mass transit enables people to live in low-density areas who otherwise could not. A massive proportion of the DC area population lives in the burbs, drives to a cheap/nearby parking garage at a transit center, and then takes mass transit into the city to work. This lifestyle would be impossible without mass transit. What makes you think that density/economic output are the main factors in how much public transit actually gets built? EDIT: I actually love public transit, but I just don't see any evidence that it does anything but encourage sprawl just like cars do. Also, public mass transit's environmental advantage over cars will vanish with electrification. What public transit does do extremely well is get people from A to B with high throughput. That by itself is highly valuable in any major city.