Transit agencies fed up with buses and passengers stuck in downtown afternoon gridlock are calling on ­Minneapolis ­officials to do more to get buses moving.

SouthWest Transit CEO Len Simich sent a letter to Minneapolis Mayor Jacob Frey’s office last week insisting the city should give priority to buses while a block of Marquette Avenue is closed for a utility project.

For the past few weeks, more than 100 buses from four transit agencies have been using S. 2nd Avenue to detour around the closure between 10th and 11th streets. The transit agencies say traffic control agents stationed at four key intersections have been letting only one or two buses pass through at a time, then allowing other traffic to proceed while other buses wait.

“It became clear on the first day that the officers were not directed to prioritize transit above any other mode,” Simich wrote. “This lack of follow through by the city has resulted in significant delays to transit service throughout downtown Minneapolis during peak traffic hours, which has left our customers frustrated wondering why more is not being done by the city.”

On Tuesday, some buses were delayed by more than 30 minutes.

Kim Keller, director of Minneapolis Regulatory Services, said traffic agents are not giving transit the snub. She said agents must consider many factors when managing traffic flow. Even when the agents are deployed, “that does not mean there won’t be congestion.”

“They are there to keep traffic moving and for people to get home safely,” she said. “This has been challenging for everybody.”

Representatives from SouthWest and other agencies, including Metro Transit and the Minnesota Valley Transit Authority (MVTA) discussed the rush-hour snarls with the city on Thursday during a regular monthly meeting.

The MVTA “supports enforcement of bus-only lanes and any measures to keep traffic flowing,” said Richard Crawford, a spokesman for the agency providing service to cities south of the Minnesota River.

SouthWest’s Operations Manager Matt Fyten said the city had a good plan in place before the construction began, but it has not delivered, and that prompted the letter. The agency on social media encouraged its riders to complain to the city.

“We were under the understanding that transit would get priority,” he said. “And that has not been the case.”

Robin Hutcheson, Minneapolis Public Works director, said she was surprised by Simich’s letter and said that the city has done everything possible to make transit run smoothly during the monthlong disruption.

In addition to the traffic control agents, she said traffic lights on S. 2nd Avenue have been timed to improve traffic flow and metered parking has been curtailed to give buses more space to maneuver.

Still, she said Public Works will look at what other steps can be taken, including extending left turn phases to allow more buses to get through on each cycle and extending the hours traffic control agents are deployed an additional hour until 7 p.m.

Hutcheson said the congestion has not been out of the ordinary until this week when thousands of commuters leaving downtown were mingling with thousands of other people streaming into town for evening Twins games.

The gridlock has been exacerbated by drivers who block intersections, she said.

“That creates a cascade effect through the entire system. Don’t block the box,” she said. “Don’t do it. It works when people wait and take their turn.”

The Marquette project is set to wrap up in early July, but Simich is concerned the issue might resurface with future road construction.

More than 40% of downtown workers arrive on public transportation, but Simich said transit ridership has dropped in recent years and will continue to slide if buses are not given priority over general traffic.