The GreenTRIP Parking Database contains parking and affordability data for over 65 residential buildings in the Bay Area. Users can filter the data by location, development type, affordability (calculated by percentage of units below market rate), nearby transit, parking availability, and more. The tool then creates printable comparison reports for buildings of interest, complete with the total number of unused parking spots and the construction costs of these spaces.

To collect the data, TransForm’s researchers surveyed property managers and developers, and counted the number of parking spaces left vacant in the middle of the night. For the 68 buildings currently in the database, the average percentage of vacant spaces per building was 31%. For some buildings, however, it was as high as 69%. The construction of all of these unused spaces cost $139,352,200, an expense that is often passed on in the form of higher rents – even for tenants who don’t own cars.