Route 1A, which is despised by North Shore commuters, carries about 60,000 cars a day past the main entrance to Suffolk Downs, Black said.

Drivers are frequently hung up at two major chokepoints, at Boardman Street south of the track, and at Bell Circle in Revere, north of Suffolk Downs.

“Boardman Street has been a serious problem,’’ said Rodney Emery, a transportation specialist at Jacobs Engineering, who has no connection to this project. “That intersection is the bottleneck coming out of the city, out of the airport, the central artery - all of them sort of converge on that point. I haven’t seen anything done there for years. They post a policeman there at peak hours to try to move things.’’

A two-lane flyover, to be paid for by the developers, would carry cars heading north over Boardman Street, with the option to turn right into the casino soon thereafter, according to Black. “It’s something that can be built relatively quickly, and we can keep 1A open during construction,’’ he said.

Emery said a flyover could help speed traffic past Boardman Street, though drivers going past the casino and heading north may still get stuck at Bell Circle.

Suffolk Down asserts that other fixes it is willing to pay for, such as improving the intersection of Routes 1 and 16 to the west of the track, would help relieve traffic at Bell Circle. Those improvements could become part of the mitigation agreements the developers, under law, must negotiate with the host communities in which the track is located, Boston and Revere, and neighboring communities, such as Chelsea.

Not everyone will embrace the track’s traffic plans. John Ribeiro, a casino opponent, said other studies suggest that traffic problems in the area would cost much more to fix than the $40 million offered by Suffolk Downs.