The often maddening hunt for parking in Bethesda’s restaurant and shopping district is about to get even worse for nearly three years when a key street and two major parking lots soon close for high-rise and underground construction projects.

The construction on two corners of Woodmont and Bethesda avenues — the epicenter of one of Montgomery County’s “downtowns” — will close two parking lots that provide nearly 300 metered spaces. The lots across from Barnes & Noble in Bethesda Row are heavily used by shoppers, diners and moviegoers, as well as cyclists and runners headed for the adjacent Capital Crescent Trail.

Construction also will close a block of Woodmont south of Bethesda Avenue for about 20 months. The relatively small but key road is used by many motorists to bypass congested Wisconsin Avenue.

The news brought wide eyes and groans from some who frequent the area.

“It’s already horrible,” said Dominic Bregenz, 36, who lives in Bethesda and said he walks downtown whenever possible to avoid having to park. “If they take that lot away, you’re really not going to have any parking.”

Starting in November, utility relocation work will close some spaces in the largest of the two lots adjacent to the trail and a Honda dealership. Workers will move the trail entrance slightly to the east temporarily and build a shielded walkway for runners and cyclists near the large construction site. The trail will remain open throughout the nearly three years of construction, the developer said.

In January, the two surface lots will close to allow for the start of construction on the two buildings. The building on the southwest corner will be five stories, with retail on the ground floor and 162 residential units above. On the southeast corner, a nine-story building will have 88 residential units and ground-level retail.

The one-block section of Woodmont will close within several weeks of the beginning of the January construction so crews can build a parking garage beneath it, the developer said. When finished in about two years, the underground garage will provide 290 tenant parking spaces and about 900 public spaces, officials said. The street also will be moved slightly to the west and narrowed to slow down traffic and help pedestrians cross more easily.

The net result will be about 600 additional public parking spaces and more high-rise living, changes that should create a more vibrant “downtown” feel, county officials and the developer said. The county, which owns the parking lots, sought developers’proposals for the 3.1 acres in 2004.

“When we develop our two buildings, they will really complete those corners and complement the existing Bethesda Row,” said Doug Firstenberg of Bethesda-based StonebridgeCarras, which is developing the two buildings with District-based PN Hoffman.

Firstenberg said the project will cost about $150 million.

The county is paying about $49 million of the garage’s $89 million construction cost, with the developers paying the rest, said Ken Hartman, director of the county’s Bethesda-Chevy Chase Regional Services Center. Revenue from downtown Bethesda parking meters will fund the project, Hartman said. No tax money is involved, he said.

To alleviate the parking crunch during construction, long-term metered spaces in the area’s main public parking garage between Bethesda Avenue and Elm Street will be replaced with shorter-term meters. Those all-day spaces used most often by local workers will be freed up for shoppers, diners and moviegoers, Hartman said. Workers will be encouraged to use farther-flung public garages served by the free Bethesda Circulator shuttle bus, which will have more frequent peak-hours service. The main parking garage will be equipped in November with an electronic system that will show drivers how many spaces are open before they enter.

“It’s going to be a wonderful addition to Bethesda,” Hartman said of the new buildings and underground garage. “The challenge is getting from here to there.”

Downtown Bethesda, including the Woodmont Triangle area a few blocks north of Bethesda Row, is home to 500 stores, 200 restaurants and 45,000 employees, Hartman said. Bethesda Row in particular has been a linchpin in the area’s transformation from a quiet suburb to a shopping and entertainment destination. The Landmark Bethesda Row Cinema attracts independent-film buffs, and sidewalks bustle on weekdays with nearby office workers running out for lunch. On weekends, the area teems with stroller-pushing families, runners and cyclists.

A few blocks from the Bethesda Metrorail station, Bethesda Row is considered a textbook example of transit-oriented development, where taller buildings with mixed uses — retail, residential and office space — are designed to create dense, easily walkable communities. The area is also scheduled for an additional southern entrance to the Metrorail Red Line station as part of the proposed 16-mile light rail Purple Line, which would start near Bethesda Row and run east to New Carrollton.

Replacing vast surface parking lots with high-rise buildings also jibes with the county’s new overall plan to focus development around transit stations to accommodate population growth while limiting traffic.

Even so, like many transit-oriented communities, downtown Bethesda has retained and even generated plenty of traffic, and the area is still absorbing thousands of vehicles from the recently expanded Walter Reed National Military Medical Center nearby.

“This area is already really, really built-up,” said Rachel Federowicz, 28, who takes her 2-year-old son downtown about four days a week for children’s classes and to play at the fountain.

“I can’t imagine a high-rise here,” Federowicz said as she carried her toddler through the biggest surface lot. “It’s going to give it a different feel.”

Danny Fleishman, co-owner of Bethesda Bagels, said he’s bracing for customer parking to become even more scarce during construction. But he said he hopes to profit short-term from hungry construction workers and long-term from the residents and workers who will live and work in the new buildings.

“Once it opens, obviously there will be more restaurant competition coming in,” Fleishman said. “But if it draws more people to the area, that’s more customers for us, too.”