ON A GORGEOUS FALL afternoon in suburban Montgomery County, Lori Feller, a management consultant and mother of a toddler, kneels in her front yard, planting flowers. The yard is tiny. It's hard by a narrow street. It's less than a minute's walk from a busy little downtown of restaurants, doctors' offices, an eight-screen movie theater, varied stores and even apartments above storefronts.

Apartments above storefronts? Walking? In suburbia? This is the new suburban dream - countering some of sprawl's environmental, economic and social ills.

Ms. Feller lives in Kentlands-Lakelands, a Gaithersburg community and Maryland's first adhering to "traditional neighborhood design" principles: more compact, walkable suburbs offering urban-like mixes of shopping, denser housing and in some cases offices. They eat up a lot less land than typical suburbs and try, not always successfully, to dethrone the car.

They also aim to promote a suburban version of the front-porch life once widespread in many cities. Sometimes, Ms. Feller admits, Kentlands-Lakelands' careful design makes it seem like an upscale "Pleasantville," but she loves that it has encouraged interaction with her neighbors. "Unless you're living in the city," she says, "you can't have that."

Scores of such communities have been built or are under way across the United States, including a half-dozen or more in Maryland. Builders embrace them because they can squeeze more units from the dwindling supply of land, sometimes putting 4,000-square-foot homes on lots of a seventh of an acre. Managed-growth advocates like them because they lessen the impact of the same numbers of suburban homes conventionally arrayed.

More than a million people will be added to Maryland over the next 20 years, resulting in an almost 50 percent increase in central Maryland's developed land and driving up the costs from sprawl for all Marylanders. Mixed-use, higher-density communities use open land more efficiently. On redeveloped land within the state's beltways or along its transit lines, they also could be a lure to potentially reverse the outward flow of population. A thousand new homes and related facilities typically eat up 750 acres of open suburban land, the Baltimore Metropolitan Council says - compared with just 277 acres for these denser developments and only 228 acres if they are on redeveloped land.

But too often in the Baltimore region, such developments - even high-end ones - run into a deep aversion to density, opposition expressed in the 50-year mass movement to large lawns and too often still steeped in class or racial fears.

Witness Maple Lawn Farms at routes 29 and 216 in Howard County. Its 500 acres could have been sliced into 2-acre lots. Instead, 1,100 apartments, townhouses and houses (10 percent for moderate-income families) and 1.3 million square feet of office and retail space will rise there. The county has already erected three schools, fire and police stations, utilities and interchanges; the project's small-lot "cottages" likely will sell for $500,000-plus. Yet Maple Lawn's larger-lot neighbors were so vehement that its developer had to endure more than 30 hearings and reduce its density.

Many suburbanites don't like the effects of sprawl, but density is fought almost everywhere: From 1982 to 1997, the Baltimore region's population grew by 13 percent, but its density fell 15 percent. In White Marsh, the Honeygo development was cut from 11,000 homes to fewer than 5,000 by foes insisting on wider lots. More than 1,000 proposed homes at the old Greenspring quarry in Pikesville were whittled to 599. In Mount Airy, new Mayor James Holt, a slow-growth advocate, scoffs at saving land via mid-rise development.

But buildable land close to Baltimore or Washington is now so dear that higher-density, mixed-use developments must be the future. In this region, they could proliferate as Baltimore County moves to replace aging apartment complexes in Beltway neighborhoods and as Baltimore tries to tear down vacant houses and amass land for redevelopment. Such designs fit particularly well with transit stops like Owings Mills Town Center, where the county has long proposed 46 acres of housing, shops and offices.

Promoting high-density residential development, now taking up only 3 percent of the Baltimore region's land, challenges suburbs used to accommodating, not containing, sprawl. Zoning and building codes often are hostile to higher densities, narrower streets, pedestrians, and mixing offices and stores with residences. Adequate infrastructure must be in place.

But most of all, a cultural revolution is needed - one in which well-designed, higher-density suburban development becomes much more widely acceptable. Until then, the centrifugal forces devouring Maryland's landscape will persist.

Tomorrow: City