The MBTA has recently opened a new elevator for their Brattle Square T Station, pictured here on Tuesday afternoon.

The first phase of a multimillion dollar project meant to increase wheelchair accessibility to the Harvard MBTA station came to a close on Thursday with the opening of a new elevator in Brattle Square, leaving behind a legacy of frustration during the 17-month-long project.

Several local businesses suffered from a loss of foot traffic during a normally busy summer season due to the construction zone at their doorsteps.

The renovation, which made the entrance to the MBTA station at JFK Street and Brattle Street accessible to wheelchairs and strollers, cost $4.1 million.

In the next phase of the ongoing project, the MBTA plans to replace the existing elevator at the main entrance to the Harvard station, near Out of Town News, with a larger glass-enclosed round lift, according to Desiree Patrice, the project manager.

The construction project was launched as part of the settlement of a class action lawsuit by the Boston Center for Independent Living and eleven individuals against the MBTA. The transportation authority agreed to construct additional elevators and escalators for several highly trafficked stations, according to Patrice. In total, the renovations are expected to cost $122 million.

In Brattle Square, workers removed the existing staircase and rebuilt it in a new location before adding the elevator. During that part of the project, from July to Dec. 2010, a fence blocked the area, obscuring the entrances of local businesses from passersby.

Stephen Zedros, manager of Brattle Square Florist, estimated that his sales dropped 20 percent during the summer of 2010 due to the construction.

Ordinarily, the Brattle Square plaza is a popular summer hangout. “It’s a big draw to have people sit out there during the nice weather,” said James Gilligan, manager of Hidden Sweets.

Several business owners said they wondered whether the construction was carried out as efficiently as possible.

To Edward P. VerPlanck, owner of Dickson Bros., the project seemed inordinately long.

“No wonder the T is in debt. They’d have an MBTA policeman standing there doing nothing,” VerPlanck said.

VerPlanck added that his hardware store, which is located across from the plaza and was not blocked by the fence, saw increased sales during the project because of some business with the construction workers.

The MBTA took steps to minimize the disruption to local commerce, posting a sign on the fence with the names of the businesses that were hidden behind it and conducting much of the work at night in order to minimize disruption, according to Patrice.

“The organization of the project was really impressive. The work was done relatively quickly, and there wasn’t much noise or construction dust that made it difficult for us to do business with our doors open,” Marley J. Brush, co-owner of Crema Café, wrote in an email.

Nan Stock, a Medford resident, used the elevator soon after it opened on Thursday.

“I’ve already seen it get used a lot. That elevator is so much more appealing than the one in the center. It’s big enough to accommodate more strollers and wheelchairs too,” she said.

In addition to building the glass elevator, the project included $1 million of work in the plaza, adding granite seating, planters, and new pavement.

—Staff writer Kerry M. Flynn can be reached at kflynn@college.harvard.edu.