CHPC initiated this report in order to assess existing research on the role of preservation and development of affordable housing in transit--oriented corridors as a greenhouse gas (GHG) reduction strategy for California. As a result of our extensive review of existing literature, we have found three important trends : 1) Lower income households are less likely to own a car, more likely than other income groups to walk or take transit, especially in transit rich areas, and have lower vehicle miles traveled (VMT); 2) living in transit--oriented development (TOD) reduces auto use and resulting GHG emissions while also lowering transportation costs; and 3) housing near transit stations is subject to more rapidly increasing rents and property values, making these areas less affordable to low income households over time.