Getting around downtown Washington — by foot, car, bicycle or bus — will get more difficult and complicated starting Sunday as the leaders of more than 40 African countries descend on the District for a summit.

It could lead to gridlock through midweek, particularly around the White House, Foggy Bottom, the Tidal Basin and the Mandarin Oriental Hotel in Southwest. Many street closures will be brief, others staggered, but officials warn that the cumulative impact could be rough for people trying to navigate the city.

Metrorail will run and all stations will be open, but some buses will be detoured. Tuesday and Wednesday are expected to be the worst days.

And, as happens when many important people visit the nation’s capital, thousands of police will deploy with the usual array of street barricades, airport-style searches, bag checks and motorcades. They will be akin to security measures during an inauguration, only over a longer period.

The Office of Personnel Management is warning federal workers about “significant disruptions” in daily commutes and urging agencies to “consider encouraging employees who can be spared from their duties to request to adjust their work schedules.” Many parking garages near events will be closed or only open to monthly cardholders. Employees of the National Academy of Sciences and the American Pharmacists Association will be able to get to their buildings only by foot.

Map of all road closures and parking restrictions in place for the Africa Leaders Summit, which takes place Monday, August 4, through Thursday, August 7, in the District.

“Driving downtown probably will not be a good idea during this period because there will be a lot of rolling closures,” said Reggie Sanders, a spokesman for the District Department of Transportation. “Motorists should pay close attention to motorcades and short-term road closures.”

They also should watch out for delays caused by street protests and lots of pedestrians. “It’s one of those events that is typical of our city, and we ask people to just be patient, try to be very aware that these things are happening and plan,” Sanders said.

The 2014 U.S.-Africa Leaders Summit is designed to strengthen ties between continents and bolster economic development and trade. This many heads of state have not visited Washington at one time since the Nuclear Security Summit in 2010, during which 40 leaders met at the Washington Convention Center. The Secret Service has issued a detailed memorandum listing road closures and describing police enforcement in broad terms. Officials also provided a color-coded map.

Officials say the big-impact days will be Tuesday around the Mandarin Oriental Hotel — 1300 Maryland Ave. SW — and Wednesday around the State Department building — 2200 C St. NW. On those days, nearby roads and sidewalks will be closed and workers, residents and hotel guests will have to submit to searches and security checks before being allowed to pass.

The area is mostly filled with government buildings, but a few shops are tucked in, including a CVS, a Potbelly Sandwich Shop and a Starbucks, all near the hotel. The manager of the Potbelly, a block from the Mandarin, said her shop would remain open, encouraged by a meeting with building representatives who told her that customers should be able to reach the restaurant on foot.

“I don’t think it’s going to be a big deal for people who are walking,” said the manager, Safaa Abida. “There are a lot of restrictions for parking, but there’s also a lot of people at the hotel. The FBI agents, the police — they need food, of course. I’m not sure if we’re going to be busy or slow, but I’m thinking we’ll be busier than usual.”

Another complication is that the Washington Nationals play at home throughout the summit, which could put an additional burden on the Waterfront neighborhood. The stadium is away from summit activities, but there will be restrictions along Maine Avenue near the Southwest Freeway that could slow evening game traffic.

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Parking will be restricted, but all bridges will remain open. There are restrictions on airspace, although none will impact commercial airlines. But people planning to sail on the Potomac River should hold off: Commercial and recreational boats will be prohibited in the Washington Channel on Monday and Tuesday from near the Interstate 395 and Southwest Freeway bridges to the Georgetown Channel entrance at the Tidal Basin.

One safety issue police won’t have to worry about is people carrying firearms. On July 26, a federal judge overturned the District’s ban on carrying guns in public places but has since delayed implementing his ruling for 90 days. D.C. Police Chief Cathy L. Lanier said the Africa summit, along with other events that draw dignitaries, is one reason carrying weapons should be restricted in the nation’s capital.

“We have a Fourth of July celebration on the Mall,” Lanier said. “We have the African Summit coming up — 49 foreign leaders that’ll be there. There are a lot of big things like that. We really need to think through what provisions are going to be valuable to us that are unique to Washington, D.C.”

Authorities compared the Africa Summit as more in line with the 2010 nuclear summit, which shut down much of downtown around the convention center. Dozens of businesses closed or were caught inside a security zone, unable to be reached by customers. Metro stations shuttered, and commuter routes such as New York Avenue were at standstills. Some residents had to show ID to reach their homes.

Police say the Africa summit should be easier, given that it is for the most part concentrated away from downtown, although a street closure in one part of the city can cause a ripple effect miles away. One bright spot is that the summit is in August, when Congress is out and much of the District is on vacation.

Mike DeBonis contributed to this report.