It wasn't too long ago when businessmen returning from their downtown offices alighted from streetcars at Fields Corner, Uphams Corner, Grove Hall and many, if not most, of the major streets in Dorchester. Those days are gone, the tracks in the roadbeds destroyed during the heyday of America's love affair with the automobile some sixty years ago.

Now urban designers and city planners are looking back on those mass transit-rich days as the end of a long evolution that American cities need to reconnect to, using new methods tied to old traditions. Or to follow the analogy, America is beginning to realize the automobile is a high-maintenance lover, and yearns again for the romance of the streetcar suburb.

In the colleges, universities, and halls of government they call this official yearning T.O.D. (Transit Oriented Development) and in recent decades the powers that be in the city, state and federal governments have begun encouraging new construction near transit lines with funding, incentives and guidelines.

Just about every section of Dorchester enjoyed growth that sprang from streetcar lines in the late 19th and early 20th centuries. Uphams Corner, Grove Hall, and Fields Corner were hubs for trolley cars, as were Franklin Park, Ashmont and Mattapan Square.

Many of today's MBTA bus lines illustrate the old routes that went from streetcar to trackless trolley to bus. The 16 Route wove through Dot from Franklin Park to Andrew Square, the 19 went from Fields Corner to Dudley Square by way of Grove Hall, and the 22 went from Ashmont to Dudley Square to connect to the elevated line that would become the Orange Line in the late 60s. Buses by the same number roughly follow all of those lines today, save the 16, which now cuts its journey short at Ruggles. These are only a fraction of the spider's web of lines that crisscrossed the neighborhood.

According to Jeff Gonyeau of Historic Boston, Inc., who has been pouring over Bromley fire insurance maps from eras leading back into the 1800s, the peak density of businesses and residents in Fields Corner was long ago, when streetcars were omnipresent.

"Just by looking over the years you can see how things got denser and denser until the 1930s," Gonyeau said. "Then, a lot of the buildings that were there are now gone. They began disappearing in the 50s, 60s and 70s."

According to information gathered by streetcar enthusiasts on wikipedia.org, the 16 Route ran its last streetcar in 1949, as did the 19. Dorchester Avenue saw its last cars circa 1930, while a few other lines lasted into the 50s, and of course the Ashmont-Mattapan high-speed line still exists. Some routes ran trackless trolleys -buses using the electric power lines - well into the 60s.

The idea of T.O.D. is not to bring back the streetcar per se, but to encourage an organic return to some of the better aspects of the streetcar stop neighborhoods of those days. Mixed-use is a buzzword: Buildings with retail on the first floor, providing more services for local residents, and residential or office space on the upper floors. Density is another, the more compact and more shopper-friendly, as the theory goes, the less need for an automobile. In the end, the city would become more efficient as a whole.

One estimate, from the Center for Transit Oriented Development, predicts that demand for housing near transit stops in Greater Boston will nearly double by 2030, the beginning of a return to urban living that could transform major cities around the country.

The market trends are already visible in Dorchester's real estate market. Housing prices have held on to their value in neighborhoods all along the Red Line, while prices in areas to the west with less transit access have plummeted. Community development corporations like Viet-AID, Dorchester Bay EDC and Codman Square NDC are all engaged in development almost exclusively along the Red Line or the Fairmount Line, not only because they agree with the T.O.D. principles, but also because the funding they seek from the city, state and federal government is often more available to T.O.D.-linked projects.

"The state has established new funding streams that have targeted funds to transit oriented development," said Joe Kriesberg, director of the Massachusetts Association of Community Development Corporations. "The additional funding has made it easier to do than projects in the past."

And the trend is national one, said Kriesberg. T.O.D. is said to help give new residents access to jobs, reduce energy consumption, and make for more economically-sustainable living situations.

"The urban opportunities for residential development around transportation infrastructure have often been tied to gentrification and push people out," Kriesberg said. "CDC's are getting the [ability] to make some developments that benefit the local residents, and not just the gentrifiers."

Private developers are following the predicted demand too. The Carruth building, built by Trinity Financial, Inc. on land next to Ashmont station on land leased from the MBTA, is the most notable local example. At Mattapan Square's trolley and bus terminus, the MBTA has carved out an adjacent site that it hopes will likewise result in a privately-developed mixed use building. And, the massive redevlopment of Corcoran-Jennison's Bayside Expo Center campus in Columbia Point - just steps from the JFK-UMass station - is using T.O.D. as a way to tout their projects "green" qualities..

"The idea is that we can create communities where the carbon footprint is significantly reduced," said the Boston Redevelopment Authority's John Dalzell, the agency's resident expert on T.O.D. "We achieve this by creating areas of greater density that are not car-dependent. Being able to live car-free is also a significant economic advantage."

Automobiles can cost anywhere from $6,000 to $12,000 a year, said Dalzell.

"When you apply that to a mortgage for a home, that has a significant impact," he said.

One Los Angeles urban planning professor, Donald Shoup, has gone so far as to call free parking a "fertility drug" for cars, arguing that the more places there are to park, the more cars will be created to park in them. He decries the common practice of requiring parking for new developments, saying it perpetuates a drain on public resources and the environment.

"When it's a practice, you start to view it as a subsidy," said Dalzell, agreeing with Shoup on some points. "The cost of a parking space, even a surface space, is $10,000 a space. For below grade or structural spaces it's $30,000 or $40,000. A lot of our roads are at peak travel capacity. You don't want the city sprawl out and some of that is not building more spaces for cars."

Another part is encouraging ground-floor retail so more services are near the home, just like the bakeries and butchers of old, he said.

When and if T.O.D. translates to an overall reduction in automobile use, the energy conserved could be considerable. And with gas prices soaring, Red Line ridership jumping as much as 10 percent over last year in recent months, scooter and bicycle sales peaking and other indicators, T.O.D. is gaining momentum all the time.