The San Francisco Bay Area has regions struggling to meet housing needs for some of the 7 million people who live in its nine counties.

Depending on the economy, the Bay Area’s population could grow to 9 million by 2040, prompting the chairperson of the Metropolitan Transportation Commission, Orinda Mayor Amy Rein Worth, to say, “Maintaining our region’s high quality of life will depend on making wise decisions about transportation, housing and land use.”

An area-wide plan to address those three elements was approved July 18, 2013 by the executive board of the Association of Bay Area Governments (ABAG) and by the Metropolitan Transportation Commission (MTC).

That document, Plan Bay Area, includes both the Sustainable Communities Strategy and the 2040 Regional Transportation Plan. Now, to help Bay Area residents learn about the plan, nine open houses have been arranged in various locations.

The nearest is in Fairfield on May 7.

Plan Bay Area wasn’t cut from whole cloth. It is the latest result of a planning process that has been in place for decades.

It is, however, the first long-range plan that meets requirements of Senate Bill 375, the landmark legislation that in 2007 said each of California’s 18 metropolitan areas must develop sustainable strategies to accommodate expected future growth by expanding housing while reducing greenhouse gas emissions from cars and light trucks, expanding transportation choices and strengthening local economies.

SB 375, signed in 2008 by Gov. Arnold Schwarzenegger, requires that Sustainable Communities Strategies promote compact, mixed-use commercial and residential development, including development of walkable and bikeable neighborhoods that are close to public transit, jobs, schools, shopping, recreation and parks.

Plan Bay Area, called a blueprint for preparing for those 2 million new residents, is required to project the region’s growth and to identify places where that growth can be housed.

Not just a description of geographic areas, the plan also is required to provide numbers associated with those needs through housing plans that allocate voluntary targets to each local jurisdiction. It also brings together two Bay Area organizations that now get to work hand in hand to address future growth.

For years, ABAG has been the organization responsible for assessing regional housing needs. Plan Bay Area includes housing and combines it with an examination of the area’s long-term regional transportation needs, which has been the charge of MTC, given to that panel by state and federal law.

By combining the two, Plan Bay Area is expected to produce a healthy regional economy, Worth said.

An outgrowth of SB 375, Plan Bay Area provides a strategy for meeting 80 percent of the region’s anticipated housing needs through Priority Development Areas (PDAs), designated neighborhoods that offer a variety of housing options that are within walking distance of frequent transit service. PDAs also are designed to assure that housing is near grocery stores, community centers and restaurants.

Some of those PDAs are large regional centers — San Jose’s and Walnut Creek’s downtown areas, for example — while others are smaller, with a boutique feel, such as Suisun City’s waterfront.

Benicia’s first PDA is the Benicia Industrial Park, chosen because of its economic importance. The next one designated by the city is the historic downtown, a blend of a variety of shopping opportunities, historic homes, apartments and other housing types.

One aspect of PDAs encouraged in Plan Bay Area is the encouragement of infill development, a way to add value to a piece of property, especially in neighborhoods.

To help cities cultivate PDAs, Plan Bay Area also comes with funding from fuel, sales and property taxes, bridge tolls and public transit fares, for the construction and production of mixed-income housing. Money from other sources is directed to transportation and other needs.

To help residents learn more about Plan Bay Area, nine open houses have been scheduled, one in each county, where public comments will be accepted.

The series began Wednesday with meetings in Pleasanton and Walnut Creek. The next two open houses will be at 7 p.m. May 6 at San Mateo County Event Center’s pavilion, 1346 Saratoga Drive, San Mateo; and at the Berryessa Community Center, 3050 Berryessa Road, San Jose.

Solano County’s meeting will start at 6 p.m. May 7 at the Hilton Garden Inn, 220 Gateway Court, Fairfield. Other open houses May 7 will be at 5 p.m. at Friedman Center, 4676 Mayette Ave., Santa Rosa; and at the Napa Elks Lodge, 2840 Soscol Ave., Napa.

The San Francisco open house will be at 7 p.m. May 13 at Hotel Whitcomb, 1231 Market St., San Francisco. And the final open house will be at 5 p.m. May 28 at Marin Civic Center, San Rafael.

Organizers recognized that some people may be unable to attend the meetings. They may contribute through social media online discussions on Facebook and Twitter; through the plan’s website, PlanBayArea.org; by calling 510-817-5757; or by emailing info@planbayarea.org.

Those who expect to attend the open houses but who need an interpreter or other assistance may make their requests three days before a meeting by calling 510-817-5757 or using 510-817-5769 for TTD/TTY machines.