California's law SB375 - incentivising public transport

In October 2008, California's Governor Schwarzenegger signed into law SB375, to limit the state’s CO2 emissions by curbing suburban sprawl and increasing transit-based development through various incentives.  In this article, Charles Lockwood explains how it works.
If a community plans walkable, mixed-use, transit-oriented growth that reduces automobile use and greenhouse gas emissions, for example, it gets moved to the front of the line for state and federal transportation funds.  If a proposed building is located near a transit line, it will have an easier environmental review process.
Given that a 2006 study of greater Chicago found that low-density auto-dependent households generates about 11.5 tons of CO2 annually, while those in rail-connected walkable suburbs generates just 2.5 tons of CO2 annually, these sorts of initiatives could make a big difference.