Picture the Bay Area 25 years from now with 2 million more people and 902,000 more apartments, condos or houses to accommodate them -- and most of it built near rail stations, bus lines, walking paths or bike lanes.
About a third -- or 286,000 -- of those new homes would be built in Oakland, San Jose and San Francisco as the big cities get bigger.
Eighteen percent of the housing would be developed in mid-size cities like Concord, Berkeley, Hayward, Santa Clara and Fremont, and in transit-friendly neighborhoods.
Seem like a pipe dream? This is the vision the Bay Area's regional transportation and housing agencies have just proposed as the first step toward creating a state-mandated plan to reduce greenhouse gases by reshaping the region to rely less on the automobile.
The Metropolitan Transportation Commission and the Association of Bay Area Governments say the release of their plan -- called the Initial Vision Scenario for 2035 -- opens a public debate about how and where the region should grow.
It's impractical to order people to drive less, planners say, but starting now on efforts to curb sprawl and build communities where people can walk to jobs, schools, stores and other destinations can rein in auto emissions.
Motor vehicles account for about 40 percent of the state's greenhouse gas emissions.
"The vision scenario makes a departure from the post-World War II development trends of rapid suburban growth into undeveloped territory," said John Goodwin, a spokesman for the Metropolitan Transportation Commission. "Under our vision scenario, 97 percent of the new housing through 2035 would be in the existing footprint of urbanized areas."
The vision is not a forecast, but an attempt to plan sustainable growth in the nine-county region, Goodwin said.
The scenario was developed over the past three years with feedback from nine counties and 101 cities on where and how they wanted development to occur to accommodate an expected population growth from 7 million to 9 million residents.
The two agencies will hold public workshops on the vision plan in each of the nine Bay Area counties in April and May, starting with one April 21 at Microsoft Corp. in Mountain View.
The 94-page vision document will provide the groundwork for a plan the two regional agencies must adopt in 2013 to meet Senate Bill 375 requirements to combat global warming. Metropolitan regions must adopt plans to achieve a 15 percent per capita reduction in greenhouse gas emissions from cars and light trucks by 2035.
Meeting that target won't be easy, though. As currently proposed, the 2035 vision would still fall short, achieving only a 12 percent reduction, planners said.
Also, the regional agencies haven't spelled out yet where to get the money needed for investments in public transit, roads, sewer, water and other improvements to serve the new transit-oriented development areas. The plan outlines several such areas, including along BART lines, El Camino Real on the Peninsula, and San Pablo Avenue in the East Bay.
Many groups say the plan is ambitious, but lacks details.
"Unless concerted actions are taken, it will remain a series of pretty maps to look at and nothing more," said Parisa Fatehi, attorney for Public Advocates, a social justice group. "In future meetings, staff need to describe actions to make this real."
Anti-congestion agencies have raised concerns that areas with new growth could be overwhelmed with too many transit passengers or drivers unless they get more money to serve the new residents the plan calls for.
"We already see some crowding," Tilly Chang, deputy director of the San Francisco Transportation Authority, said at a meeting last week on the 2035 vision. "Crowding is another term for people who can't get on the bus or train."
The 2035 vision plan anticipates much more frequent bus and train service on Bay Area transit systems, yet most of those systems have reduced service in the past three years due to money shortages.
Regional officials said they plan to work more on the funding issues. It's easier, they said, to plan how to accommodate growth if the region can agree on what and where it will occur.
"This is the beginning of a conversation about how our region will grow," Goodwin said.
In drafting the vision 2035, the two regional agencies relied heavily on city and county recommendations on where to plan new housing.
"The plan reflects local priorities on where to provide housing for our children and grandchildren so they can afford to live in the Bay Area, and not have to spend three hours a day commuting to work," said Amy Worth, the Metropolitan Transportation Commission vice chairwoman, who also sits on the Orinda City Council.
More retiring baby boomers and young urban dwellers want smaller homes than in traditional suburban houses, authors of the vision said.
Some large new homes still will be built, but fewer than in the past.
The plan envisions 36,000 new housing units annually in the Bay Area over the next 25 years, a sharp increase from the 21,000 new units constructed each year in recent decades.
Santa Clara, Alameda and Contra Costa counties would lead in new housing.
Santa Clara County's housing units would increase 41 percent from 613,9000 to 867,000, while Alameda County households would grow by 38 percent from 557,700 to 770,400. Contra Costa housing units would increase 39 percent from 392,700 to 546,000.
Nearly 30 percent of Contra Costa's growth would occur in eastern Contra Costa, where much of the housing would be built near BART stations or planned eBART stations that call for a BART diesel train service east of Pittsburg.
The region's struggling economy will recover, authors of the plan said, and the number of Bay Area jobs will increase 37.4 percent to 4.49 million jobs by 2035.
Doug Kimsey, MTC's planning director, said transit oriented development already is occurring in many places, including near BART stations in Dublin, Walnut Creek, Pleasant Hill, and the Fruitvale station in Oakland.
The commission has provided some $89 million over the last three years in grants to promote transit-oriented development.
"A lot has occurred," Kimsey said, "but more needs to be done.
Public workshops on the 2035 scenario for Bay Area growth will be held in each of the nine Bay Area counties in April and May. East Bay meetings are:
Alameda County: 5:30 to 8:30 p.m. May 19 at the David Brower Center, 2150 Allston Way, Berkeley.
Contra Costa County: 9 a.m. to noon May 7 at the Concord Senior Center, 2727 Parkside Drive, Concord.
Solano County: 5:30 to 8:30 p.m. May 4 at the Solano County Events Center, 601 Texas St., conference room A, Fairfield.