New traffic patterns and Metrobus detours are now in place near the MGM casino site in southern Prince George’s County.

The construction of the proposed $925 million gaming facility, which is expected to begin this summer and last about two years, has prompted some lane closures and changes near National Harbor.

National Avenue and Harborview Avenue, which run parallel to each other, creating a sort of loop around the casino site, have become one-way roads. Each road had two lanes in each direction, but MGM late last week began to put up a barrier between the uphill and downhill lanes.  The company said construction vehicles will use the two inside lanes and  regular traffic will get by on the two outside  lanes.

This new traffic pattern will remain in place for the duration of the construction, state and MGM officials said. MGM National Harbor is slated to open in July 2016.

“We don’t expect it to be a huge traffic impact.  This will separate the construction vehicles from the regular vehicles, which is a good thing,” Maryland State Highway Administration spokesman David Buck said. He said the agency approved the change about a month ago in anticipation of an influx of construction equipment at the site.

MGM is essentially taking away two travel lanes from the public on Harborview and National avenues, however, Gordon M. Absher, a spokesman for MGM Resorts International, said the company is only taking away the lanes that service a private road that bisects the 23-acre parcel, and that travelers in the area used to crisscross from Harborview Avenue to National Avenue. That private road is now closed, he said.

“We are not taking any lanes away from commuters,” Absher said. “You mess with somebody’s commute and that’s a big deal, so we have treated this like the big deal that we know it is. We have been very careful to make this changes as innocuous as possible.”

Access to an Interstate 295 ramp from Harborview Avenue will not be affected, Absher said.

When the construction is complete all lanes will reopen as one-way to provide a circular traffic pattern around the luxurious casino resort.

MGM said it needs the road space for construction vehicles and equipment.  Crews began to prepare the site for construction in April, putting up a fence around the 23-acre parcel overlooking the Potomac River. Absher said that work will increase this week with the removal of power poles and land leveling.

As a result of the construction, Metro also is making a few changes to its bus routes serving National Harbor. 

The transit agency has discontinued one bus stop served by the NH1 and NH3:  The westbound Oxon Hill Road and Harborview Avenue stop.  Bus riders traveling to Tanger Outlets can use the bus stops at Oxon Hill Park & Ride and the eastbound Oxon Hill Road and Harborview Avenue, Metro said.

Buses traveling eastbound toward Branch Avenue or Southern Avenue are not affected.  But buses traveling westbound from the Metro station to National Harbor will be detoured to avoid the construction area near the casino.

Some residents who live near the site said they were surprised to hear about the new traffic patterns and said they worry about the impact of the changes and construction vehicles on congestion on Oxon Hill Road and Indian Head Highway.  Ron Weiss said residents learned about the detour plans when the signs went up a few days ago. MGM said it put up signs about the changes three weeks ago.

MGM, however, is still in the process of obtaining approval for the project before it can start building. The Prince George’s County planning board gave the green light to the project last month, but the proposal is now headed to the County Council for approval. Construction could begin next month.