Transform's New GreenTrip Parking Database

Transform is an Oakland-based advocacy group pushing for better land use and transportation policies. The organization sampled 68 multifamily housing development parking structures throughout the San Francisco Bay Area, varying in location types. Sites were counted late-night, mid-week, when residential parking lots would be at their fullest.

The intuitively mapped database provides information "about the number of parking spaces per unit, how much of that parking sits empty, what percentage of the building is affordable housing, whether residents pay for parking separately from their rent, what level of transit service is available nearby, whether residents are offered transit passes or carshare membership, what if any parking management exists on surrounding streets, and other data relevant to parking usage," writes Melanie Curry for Streetsblog.

Todd Litman [a Planetizen blogger] of the Victoria Transport Policy Institute calculated construction costs for parking spots, which "[f]or surface spaces, the cost for each one is around $20,000; garages and structures cost $50,000 per space; underground spaces can cost $80,000 per space."

Transform found that across the 68 sites in their GreenTrip Parking Database, "on average 31 percent of the spaces go unused. That’s 867,900 square feet of space that cost an estimated $139 million to build. No wonder parking is a major contributor to the costs of building affordable housing, as identified in a new report [PDF] from four state agencies, including the Department of Housing and Community Development and the Housing Finance Agency."