Promoting Equitable Transit-Oriented Development and Mobility Corridors Act This bill addresses equitable transit-oriented development designed to create and support communities of opportunity that enable all residents regardless of income, race, age, and ethnicity to benefit from living in connected, healthy, vibrant places connected by public transportation. Additionally, such development is designed to promote a mixture of housing (including a significant level of affordable housing), office, retail, and other amenities as part of a walkable neighborhood generally located within a half mile of quality public transportation. The Department of Transportation must establish an Office of Equitable Transit-Oriented Development and Mobility to carry out an equitable transit-oriented development and mobility competitive grant program to provide technical assistance grants for states carrying out equitable transit-oriented development and mobility projects. To be eligible for assistance states must develop a plan for equitable transit-oriented development and mobility corridors that includes identifying priority investment areas with a need for a comprehensive investment strategy to keep and revitalize existing neighborhoods and corridors while maintaining and enhancing housing and transportation affordability and creating equal opportunity for existing residents and businesses. The bill also modifies provisions relating to the rehabilitation tax credit, including allowing a 15% credit for non-historic buildings within a half-mile of public transportation facilities.