In this file photo from February 2016, construction continues on the MGM National Harbor resort and casino. (Sisson Studios /Courtesy of MGM National Harbor )

Vehicle traffic to National Harbor could more than double when MGM National Harbor opens later this year, according to projections, exacerbating a growing congestion problem in southern Prince George’s County where new development has added thousands of commuters in recent years.

If projections hold true and up to 20,000 daily visitors frequent the gaming resort, there could be backups in the local and regional road network with heavier volumes on Interstate 95 around the Woodrow Wilson Bridge on the Maryland-Virginia border.

National Harbor and casino officials said Wednesday that $10 million in road improvements — from road widening to new interstate access — to be completed before the resort’s opening will help.

“Certainly there will be some congestion,” said Kent Digby, vice president of operations at National Harbor, which owns the land where the casino is being built. “With the improvements, the road system will be more than capable.”

As many as 90,000 vehicles enter National Harbor during an average week, according to the developer, and that number could rise to 180,000 when the $1.4 billion gaming resort opens in December, Digby said. Traffic during the weeks following the opening is likely to be especially heavy, officials say.

“People will make mistakes, and that adds to some confusion and delays,” Digby said. “It doesn’t mean the roads aren’t capable. That means the customers stopped and asked for directions and slowed down the traffic,” he said. “Once that learning curve happens, things usually get back to normal.”

The stretch of the Capital Beltway nearest to MGM National Harbor has seen some of the biggest spikes in traffic volume in the Washington area in the past seven years. Traffic volumes on the interchange, just north of the Wilson Bridge, grew by 27,000 vehicles a day from 2009 to 2015, according to a AAA analysis.

Besides daily commuters, National Harbor, which has become a top entertainment hub, already attracts thousands of visitors every week, and special events there have created miles-long backups. Residents and community leaders fear that the additional casino traffic could overwhelm the road system.

Even with a plan that pushes the use of buses, shuttle service and other modes of transit, officials expect that the bulk of visitors will drive to the facility. MGM is also adding about 3,600 new workers to the area.

“The big question is, ‘Will this be enough to offset the concerns of neighbors rightly worried about traffic impacts near their homes and property?’ ” said John B. Townsend II, spokesman for AAA Mid-Atlantic. “Will it prevent this corridor from quickly becoming one of the biggest choke points and bottlenecks in the metro area?”

The casino, Maryland’s sixth, is under construction on a 23-acre parcel overlooking the Potomac River, with access to the Beltway and Interstate 295. It is touted as one of Maryland’s top economic development projects that could draw thousand of visitors and spur more economic development.

National Harbor resident William Nuckols said he is most concerned about special events MGM plans to hold, such as boxing matches and concerts.

“National Harbor already struggles with dealing with special events,” Nuckols said, and minor fender benders or security problems create major backups. In April, the Wilson Bridge was shut down for about three hours as police investigated a suspicious package, and traffic was backed up for about eight miles.

The opening of Tanger Outlets in 2013, just across from the casino site, created even more traffic.

Projections suggest the facility could generate $40 million to $45 million in tax revenue for the county. Slated to open in December, though no official date has been announced, MGM is bringing Las Vegas-style gambling to the capital region with a casino that will have 3,600 slot machines and 140 gambling tables. It also has a 300-room hotel tower, a day spa, shops, and restaurants by culinary headliners José Andrés and brothers Bryan and Michael Voltaggio.

On Wednesday, dozens of workers were landscaping and paving the outdoor casino grounds, and as many as 2,300 were said to be working on areas including electrical and IT systems or loading the kitchens. Meanwhile, another set of workers were at nearby intersections working on the road improvements, including widenings, a new access to the National Harbor complex from the Wilson Bridge, and new signage. National Harbor officials said 16 projects are underway as part of the effort and that they are expected to be completed by Dec. 1.

MGM officials said they are preparing to deploy technology and manpower in the days leading up to the resort’s opening, the day of and in the weeks after. They said messaging boards will be installed to communicate new traffic patterns to residents and visitors. Dozens of police are expected to manage traffic on opening day and in the weeks following, as well as during special events at the facility.

Still, casino officials are encouraging visitors to plan ahead, arrive early, leave late and use other modes of transportation, including ride-hailing options and public transit. Metro is adding a new bus line next month that will connect the resort and National Harbor to Old Town Alexandria and Metro stations across the bridge.

“Plan ahead, and definitely don’t let the traffic get in your way of having fun,” said Mark Moore, executive director of security at MGM National Harbor.

“We have worked to put together a plan to handle the volume,” he said, but he declined to comment on whether the road infrastructure is ready.

“All that I can speak to is the plan that we worked collectively to keep traffic flowing, and we will do that to our best ... We are experts at entertainment. We leave the transportation stuff to the transportation experts.”

Casino officials say that even if there are 20,000 visitors a day, not all of them will arrive or leave at the same time. The staff shifts have been planned to start outside rush hour, and the events at the 3,000-seat theater will be programmed to start after 7 p.m.

“It is not like 10 to 15 thousand people are coming at once. That is over a 24-hour period. Some of those people will come at 11 p.m. at night,” Moore said.

The facility has about 5,000 parking spaces. But National Harbor says a total of 16,000 will be available in the area by the time MGM opens. Construction of 800 spots is underway. National Harbor will provide a circulator bus from the waterfront area to the casino and the nearby Tanger Outlets.

In the casino, officials say, they have technology to speed parking and the entry and exit process. As part of the road improvements, National and Harborview avenues, which run parallel and are being renamed, will be turned into one-way roads with traffic flowing in opposite directions, creating a loop around the casino site. MGM has built a new road connecting Harborview Avenue north to National Avenue as an alternate to using Oxon Hill Road.

Drivers on the interstate will see more signage directing people to the casino exit. Officials say they also will have drop-off spaces for taxi, Uber and Lyft and Metrobus.

Officials anticipate Friday and Saturday evenings will bring the heavier casino traffic.

The plan unveiled Wednesday includes a new inbound access lane from the Wilson Bridge into the complex, some road widenings near the casino site to add dedicated lanes for the casino traffic, and new signage on the interstate.

“There is too much focus on whether we can get to the outlets or the casino. But the real question is, ‘Can we move through the area at all?’ ” said Nuckols, the National Harbor resident. “None of that stuff seems to be very worked out.”

Ron Weiss, a community activist who has been advocating for road improvements, said the $10 million investment is encouraging, but he said he hopes the county can organize its resources quickly enough to control the traffic that will be generated.

“This is happening during the Christmas shopping season. Tanger Outlets will be busy. There is going to be a whole lot of traffic in the area. If traffic is bad today, it’s going to be terrible in two months.”