San Diego's affordable housing crisis has led to the ADU Bonus Program, permitting more Accessory Dwelling Units (ADUs) per property if they include affordable units. Since 2021, over 4,000 permits have been issued. The city's ADUs can be up to 1,200 square feet, and the permit process for affordable housing is being streamlined. Other cities are considering San Diego's model, focusing on specific areas and local median income for deed restrictions.