The 42nd Street Singers entertain shoppers with Christmas carols at the Bethesda Row Fountain on Christmas Eve. (Sarah L. Voisin/The Washington Post)

Downtown Bethesda is the economic engine for Maryland’s most prosperous county, fueled by law firms, financial service companies and multimillion-dollar condos. But the attractive open space and pedestrian traffic envisioned by planners two decades ago can be found in only a few spots, mainly Bethesda Row.

The rest — including the two-mile stretch of Wisconsin Avenue between Bradley Boulevard and the National Institutes of Health — is dominated by boxy office buildings and soul-crushing traffic.

A new long-range land-use plan, to be taken up by the Montgomery County Council in January, offers an un­or­tho­dox approach to completing the vision of Bethesda laid out by planners in 1994: A “garden,” with hiking and bike trails and mixed-income housing, where visitors and residents walk to the Metro “on brick sidewalks under leafy trees.”

The plan places new emphasis on design and environmental sustainability and would require property owners to pay for parks and affordable housing to get permission to build bigger and taller — up to 29 stories along the neighborhood’s central artery.

The hope is that the downtown Bethesda of 2035 will truly be greener, more walkable and architecturally striking. In other words, a significant change.

“From an aesthetic standpoint, Montgomery County is not a place to be really proud of,” said Edward McMahon, senior resident fellow at the Urban Land Institute. “It’s not known for good design.”

In the past, when the county has updated its land-use plans, it awarded specific levels of density — the amount of allowable construction — to each individual property.

Under the new plan, all additional density, 4.6 million square feet, would go into a central pool.

To tap into it for their projects, property owners would have to pay a $10-per-square-foot “park impact” fee that would finance the acquisition of new green space. They also would be required to set aside 15 percent of all new apartments as affordable or workforce housing (instead of the usual 12.5 percent) — meaning that prices would be within reach of families making between 60 and 120 percent of the area’s median income, in a neighborhood where new apartments rent for an average of $2,750 a month.

Construction in the downtown core would also have to be environmentally sustainable and pass muster with a design review panel.

“Wisconsin Avenue should be something special,” council member Roger Berliner (D-Potomac-Bethesda) said.

Under the new plan, the Bethesda home of Dee Harris could eventually face a 14-story apartment tower. (Sarah L. Voisin/The Washington Post)

Planning director Gwen Wright, who shaped the concept with her staff and planning board chair Casey Anderson, said the approach was “sort of unheard of” in the county.

“The tradition in Montgomery is you do a plan and everyone just gets their zoning handed to them and off you go,” she said. This time, “we aren’t just giving the zoning away.”

The development community, accustomed to receiving additional building capacity as a matter of course when master plans are redrawn, reacted unfavorably at first. But most seem to have accepted the trade-off: height and density in exchange for green space and attractive design.

“We’re big believers in Bethesda,” Jad Donohoe, vice president of the Donohoe Cos., told the council at an October hearing. The company recently moved its corporate headquarters to Bethesda, and it owns or holds contracts on seven downtown properties there.

Excitement about the area’s potential stems in part from Marriott International’s decision to move 3,500 employees to new corporate headquarters near the Bethesda Metro station by 2022.

But plans for a taller, denser Bethesda have touched off alarms in the affluent “edge” neighborhoods just east of Wisconsin, including East Bethesda and Chevy Chase. Residents fear looming high-rises will block the sun, casting shadows over their homes.

A community group, the Coalition of Bethesda Area Residents, has examined the county’s data and concluded that the new density allocated under the plan could sustain 28 new buildings of 20 stories or more. That would place Bethesda’s skyline second only to Baltimore in the Washington region, surpassing Silver Spring, Tysons Corner and Rosslyn.

County officials said that kind of runaway high-rising would not be possible, however, because of the plan’s unusual system for allocating density from a single, limited pool.

Scott Fosler, mayor of the town of Chevy Chase, said residents understand and buy into smart growth — the concept of curbing sprawl by clustering the highest commercial and residential densities around mass transit, especially in close-in locations such as Bethesda.

“I don’t have any doubt these people are well-intended and they have what they see as exciting planning ideas,” Fosler, a former County Council member, said of Montgomery’s proposal. But smart growth isn’t defined solely by density, he said. “It is defined by enhancing the quality of life for all residents of the county, including those of us who live near areas slated for intense development.”

Dee Harris, 58, lives in a Cape Cod at the corner of West Avenue and Ridge Street, across the street from the rear of a retail strip on Wisconsin near Bradley Boulevard. Under the county blueprint, her home could eventually face a 14-story apartment tower.

Harris, whose home has been in her family for four generations, remembers a smaller, sleepier Bethesda. Her father used to tell stories of throwing a paper route on Old Georgetown Road when the street was only dirt.

“I’m not anti-development,” said Harris, who has spent her career in international economic development. “Planning principles should not just be about just growth. They should also be about looking at the impact on the edges.”

County officials say that height would be focused along Wisconsin Avenue, tapering down as it reaches residential streets.

The Bethesda coalition wants the new height and density concentrated closer to the Metro station. But planners said the edge communities are too close to Metro to exclude. Bradley Boulevard, the southern tip of the 450-acre plan area, is eight-tenths of a mile from the Bethesda Metro.

The idea, said planning board chair Anderson, is to make the “walk shed” — the area that can be conveniently traveled by foot to a given point — as compelling as possible, with more attractive, pedestrian-friendly streets.

Anderson cited his own situation in downtown Silver Spring, where his home is about a block from the Point, a 16-story, 190-foot apartment building on Georgia Avenue.

“That sounds like a lot of height in very close proximity,” he said. “I think if you were to stand in my front yard, I don’t think you’d experience that building as overwhelming or oppressive. It’s a tall building, but it’s not casting a long shadow.”

Fosler pointed out that the high-rise sits on the far side of Georgia Avenue, a four-lane road. The new Bethesda buildings would be much closer. And, he adds, the Point was already there when Anderson bought his Victorian.

“All these things are different,” Fosler said. “Casey has his own preferences and tastes, and that’s fine.”

Edge residents also are worried about the traffic that could be generated as the county’s plan is put into action.

The plan projects that Wisconsin Avenue and the intersections along the corridor can accommodate the additional vehicles. But those forecasts assume a completed Purple Line light-rail project, with a station two blocks from the existing Metro stop. It also anticipates upgraded Metro service and improvements to Interstate 270, about five miles to the northwest.

For residents of Chevy Chase and East Bethesda, who say they already are held hostage by traffic on Wisconsin during peak hours, the analysis is unrealistic, especially given the ongoing struggles with Metro funding and operations and an uncertain climate for the Purple Line and road projects.

Maryland transit officials put the Purple Line’s late-October construction start date on hold after a federal judge ruled that the state hadn’t properly considered how Metro’s declining ridership might affect the light-rail line. The ruling came in response to a lawsuit brought by two Chevy Chase residents and a trail advocacy group.

Planning director Wright said she was “sympathetic” to neighborhood concerns. She acknowledged that if the Purple Line is scrapped, allowable densities would have to shrink.

“But I do believe that we have to not just think about a particular traffic situation at a particular moment in history,” Wright said. “This plan is supposed to be a vision for the next 20 years. We have to look to that vision.”

The council’s Planning, Housing and Economic Development Committee is tentatively scheduled to hold its first session on the Bethesda plan Jan. 23.