Parking requirements should have a logical relationship with observed levels of parking use and with goals related to transportation, land use, and housing. These requirements are important elements of transportation policy because they influence vehicle ownership rates, travel choices, and mobility options. These local ordinances also shape land use outcomes, such as density, and social outcomes, such as housing affordability. This paper reports on a study of parking requirements for income-restricted, affordable multifamily housing. This form of land use is of particular interest because of its cost sensitivity and controversial nature. The study reported here used household surveys and overnight occupancy counts to assess the use of parking across varied types of income-restricted, affordable housing in the city of San Diego, California. Overall, the use of parking was found to be slightly less than one-half the rate for all rental units in San Diego but varied across affordable housing types (e.g., for families versus for seniors), location (e.g., access to mass transit, opportunity to walk), and bedroom count. This paper concludes with a discussion of methodologies to measure parking use and suggests a sequential policy process to establish affordable housing parking requirements.