As the promised end date for Nicollet Mall construction nears, costs for the $50 million downtown Minneapolis project are still climbing.

A City Council committee authorized $2.1 million Tuesday to cover unexpected costs for design changes, extra man hours and more landscaping supplies. The overhaul of the city’s signature corridor from Grant Street to Washington Avenue is still under budget.

This isn’t the first time city leaders have approved more money for Nicollet Mall. Since May 2016, a series of change orders including contract extensions, design modifications and bigger trees has led to nearly $4.7 million in added expenses. The total cost is now about $41 million, city records show.

Don Elwood, Minneapolis’ director of transportation and planning, said he anticipated there would be unexpected costs and planned the project budget accordingly.

“They’re the known unknowns,” he said. “I knew we were going to have this sort of thing in the budget.”

State grants, city funds and property owner assessments are paying for the project. About 15 percent of the $50 million budget — $7.5 million — was set aside to cover unexpected costs, Elwood said.

Construction work continued along Nicollet Mall in downtown Minneapolis on Tuesday.

Five contracts have been amended in the past 15 months for services including design, construction, project management and landscaping. The full council will vote to authorize the additional $2.1 million on Aug. 31.

Robert Sniegowski, a principal at CliftonLarsonAllen who worked in the construction industry for 24 years, said planned contingencies vary from project to project. When contractors have to account for things like soil conditions, multiple utilities and traffic conditions, those costs get bigger.

“It should not come as a surprise that you would have a higher amount of change orders on an urban project like that one,” he said.

Nicollet Mall is scheduled to be largely complete by November, a little more than two years after the corridor closed to vehicles. During that time, city officials have emphasized to frustrated pedestrians and street-level business owners that construction is on time and on budget.

The project hit a roadblock early on when the only bid came in $24 million over budget. Splitting the contract into smaller pieces, shifting some costs to Metro Transit and deciding to use concrete instead of costly pavers got the project back on track.

The revamped corridor, designed by New York-based James Corner Field Operations, will include public art, special lighting, seating areas and hundreds of trees.