For the most part, NYC is densely populated with multi-family dwellings. Suburban sprawl isn't an issue.

Since most of the money comes from private sponsorship, I wonder how much influence the sponsors had over location of bike-share stations.

Citibike officials reject the idea that bike share is inherently classist, but a quick glance at the map shows bike stations are not prevalent in low-income neighborhoods. Of course, the program is very new -- lots of wealthy areas don't yet have Citibikes.

This recent article from Streetsblog gives some insight:

http://www.streetsblog.org/2013/09/1...yc-bike-share/