If Plan Bay Area includes additional housing units in my community, does this guarantee that those units are going to be built?

No. The pace at which new housing is built will be determined by various factors, including local zoning, the financial feasibility of building the new housing permitted under this zoning, and ultimately the decision by a city council, town council, or board of supervisors to approve each housing project. Cities and counties will continue to retain all control over local building decisions following adoption of the Plan.  Over the long term, communities may change zoning, provide incentives for developers, or adjust other land use policies to increase or decrease the feasibility of building the levels of housing projected in the Plan.