District officials are reserving thousands of on-street parking spaces for residents on weekdays in the city’s most crowded neighborhoods, part of an aggressive effort to limit spots for visitors.

The restrictions are a slice of a city strategy to promote bicycling and mass transit while increasing the odds that residents can find parking. The changes, which could affect as many as 10,000 spaces, come as the city eliminates some on-street parking to make room for bicycle lanes and prepares to set aside hundreds of meters for the disabled.

“That is the sign of the future, that discourages car ownership,” said D.C. Council member Jim Graham (D-Ward 1).

The most immediate changes are occurring in Graham’s congested ward, where the D.C. Department of Transportation is essentially eliminating half of the visitor parking spaces on weekdays in neighborhoods such as Columbia Heights and Adams Morgan and parts of the U Street corridor.

Under the regulations being implemented over the next month, one side of the street in 550 blocks of Ward 1 will be reserved for Ward 1 residents with valid parking permits from 7:30 a.m. to 8 p.m. Mondays through Fridays.

Nonresidents will have to park on the non-reserved side of each block, where two-hour time limits will be enforced. And in some Ward 1 neighborhoods, DDOT is considering community requests to extend the restrictions through the weekend.

Graham said the restrictions, authorized by the council two years ago but just now being implemented, are designed to make sure there is sufficient on-street parking for residents in a rapidly developing part of the city.

“People are not able to park in Ward 1 now, so what we are doing is striking a balance in favor of those who are residents with stickers who paid for them,” said Graham, noting that similar restrictions are in effect in parts of Capitol Hill.

Although finding on-street parking in the District has challenged drivers for decades, the changes in Ward 1 underscore efforts by Mayor Vincent C. Gray (D) and D.C. Council members to manage parking.

In the 15 months after the 2010 Census was completed, the District gained an estimated 15,000 residents. Although planners say many new residents are choosing to live car-free, new development has put a strain on the supply of parking spaces.

“There are only so many parking spaces on streets, and eventually there is going to be a time when the numbers don’t add up anymore or demand way overexceeds supply and we have a problem,” said Angelo Rao, manager of the District’s parking and streetlight program.

Rao said the new revisions, which will affect as many as 20 parking spaces per city block, are driven both by residents’ concerns about a lack of on-street parking and a broader city policy to encourage less vehicle traffic. Some of the changes are starting to cut into the stock of 18,000 metered parking spaces.

Last month, DDOT completed the L Street bicycle lane, reserving a dedicated eastbound lane for bicyclists between New Hampshire Avenue and 12th Street.

The new bike lane resulted in a loss of about 120 metered parking spaces downtown, though DDOT officials say they lessened the impact by adding about 70 meters in other downtown areas.

Before summer, DDOT hopes to have completed a similar westbound bicycle lane on M Street NW, which could further constrict available parking in the central business district.

Leona Agouridis, executive director of the Golden Triangle Business Improvement District, said city officials are working closely with downtown merchants to manage the impact of the changes.

“The city is trying to accommodate a changing transportation environment, and they have a strategic plan for how we are going to accommodate a lot of new realities,” said Agouridis, who noted that there are 25,000 garage spaces in the central business district.

But council member Marion Barry (D-Ward 8) said he is concerned that the bike lanes are taking too many on-street parking spots, which remain more economical than garage spaces that can exceed $20 per day.

“We need bike lanes, but we also need parking,” Barry said. “These parking lots are killing us for $30 a day.”

Gray, however, set a goal this year of having 75 percent of all trips in the city take place on foot, bicycle or public transportation by 2032. The mayor also has pushed to make the District a nationwide model in reserving city parking meters for disabled motorists.

The council is considering setting aside about 11 percent of meters with red tops for motorists with handicap permits. Some opponents fear the change will make it more difficult for non-disabled drivers to find on-street parking.

“It’s just not about creating as much parking as possible,” Pedro Ribeiro, Gray’s communications director, said of the mayor’s overall strategy. “The city is growing, and if every single one of these new residents had a car, there wouldn’t be enough parking for everyone, so the idea is to build neighborhoods where you don’t need a car.”

But the new regulations could add more confusion to the array of parking restrictions that at times baffle even DDOT officials.

Last week, the city posted parking signs in the 1100 block of 15th Street NW, next to the 15th Street bicycle lane, that said, “Zone 2 residential parking permit only.”

Neither Rao nor other DDOT officials could explain what the signs mean or say whether non-Ward 2 residents can park at the meters that line that street.

“I am trying to figure out what the rationale is,” Rao said. “Was it appropriate? . . . Was it a mistake?”

In Columbia Heights, Anita Taliferro Swanson and her husband, Gregory Swanson, park in a garage and say neighborhood parking problems have worsened over the years. The Swansons, who have lived in the 1100 block of Columbia Road for 20 years, are skeptical that the new rules in Ward 1 will make much difference.

“We remember when everyone promised the construction of Metro would cause parking to get better,” Anita Swanson said, referring to the 1999 completion of the Green Line station in Columbia Heights.

“But how are you going to tell people in America to give up their car?”

DDOT is hosting a “parking summit” Dec. 4 at Judiciary Square to solicit residents’ suggestions for managing parking. The event runs from 6 to 8 p.m.