By Mark Arsenault Globe Staff

Suffolk Downs would build a two-lane flyover on the northbound side of Route 1A to relieve one of its most consistent bottlenecks, as well as add lanes, lights, and other improvements around the track to help carry the traffic created by its proposed casino resort, track officials said Friday.

The flyover would allow drivers to bypass the Boardman Street intersection, which is regularly tied up during the morning and evening rush hour. Other measures to reduce traffic could include new lanes and traffic signals, as well as an incentive program to encourage casino employees to use public transportation.

Increased traffic has been one of the top concerns raised about a proposal to expand the 77-year-old thoroughbred horse track into a casino resort, by adding hotel rooms, restaurants and amenities, and 200,000 square feet of casino games.

The track has promised to commit $40 million to improve roads and intersections around the site. The Route 1A project, which would cost $30 million to $35 million, is the centerpiece of Suffolk Downs’ traffic plan. Other improvements would be the subject of negotiations with local communities, said Chip Tuttle, the track’s chief operating officer.

Suffolk Downs expects that its $1 billion resort, when complete, would generate about 10,000 car trips on weekdays and up to 15,000 trips on a Saturday, according to R. David Black, senior project manager at Vanasse Hangen Brustlin Inc., of Boston, the track’s traffic consultant. An estimated 55 percent of the casino’s traffic would come on Friday, Saturday and Sunday, Black said.