The $50 million makeover of Nicollet Mall in downtown Minneapolis is entering a critical phase as its organizers try to win the support of the property owners and businesses being asked to pay half the project’s cost.

Retrofitting the city’s most recognizable retail corridor is critical, proponents say, to capitalize on the dramatic resurgence of office and residential development in Minneapolis’ urban center. The emerging vision for the project calls for a streetscape that is more pedestrian-friendly, punctuated by more trees and artistic features.

Most property owners and businesses say they support renovating the city’s signature 12-block street, which hasn’t been updated since 1990. But they are growing anxious for details on the $25 million assessment that they will shoulder.

“We hope the improvements that they are suggesting in the design will … make our properties more appealing,” said Kevin Lewis, executive director of the Greater Minneapolis Building Owners & Managers Association. “But we are very sensitive to the cost and the impact it would have on the tenants.”

To address the growing backlog of questions, the Nicollet Mall project team unveiled a revised design Thursday night at a public forum. Designers highlighted several changes to the plan, such as turning walled, hexagonal transit stops into transparent, open-aired rectangular structures, to address concerns over crime.

“We are really in a refinement stage at this point,” said Peter Brown, the project manager hired by the city. “The design was great to begin with and now it’s even better.”

A reinvigorated Nicollet Mall would generate an estimated $106 million in additional annual spending and 860 new jobs, according to a city-commissioned study.

Earlier this year, the Minneapolis Downtown Council adopted a resolution to match the public contribution dollar-for-dollar via an assessment on nearby properties. The Legislature committed $21.5 million toward the project, with the city of Minneapolis kicking in $3.5 million to round out the public’s half.

Unlike the Downtown Improvement District tax that is levied against commercial property owners, the Nicollet Mall assessment will include all classes of property, including residential and hospitality. Only federal property will be exempt. The cost is often passed on to the building tenants in rent rates.

Steve Cramer, president and CEO of the Downtown Council, said the assessment model is still in the works and will need City Council approval. He anticipates a multitiered formula based on two primary factors: class of property and proximity to the mall.

“We will see how people react. Anytime there’s a new tax, it gets people’s attention, but I don’t think the cost will have a huge impact,” Cramer said.

New-York based James Corner Field Operations, the project’s landscape architect, is the same firm that designed the much-heralded High Line Park in New York City. In an effort to make the milelong mall more pedestrian-friendly, the team is creating a straight, seamless walkway that hugs the buildings instead of the curvaceous street.

And to keep that passageway aligned, all restaurant patios will be moved away from the buildings and put streetside.

Some restaurant owners have expressed concerns that separating the patios from the eateries could cause problems for waitstaff.

Controversial plans for stairs that would have brought foot traffic out of the skyways and onto the street have been removed over liability concerns.

Brown emphasized Thursday the project should stay within budget because of the design’s flexibility.

“If we are over budget, we may take an alternate to use a different type of pavement on a road. If we are under budget, we might add in a feature or better quality light fixture that is not part of the base project’s budget,” he said.

Still navigating a plurality of voices, the project is moving forward. Short Elliott Hendrickson Inc., known as SEH, was recently hired as the project’s construction manager and the assessment model should go to City Council for approval in the first quarter of 2015.

A consultant has been brought onboard to integrate streetcar-ready plans for beneath the road’s surface should that project take root, but said tracks won’t be laid during the redesign. The city of Minneapolis is exploring a streetcar system on Nicollet and the redesign team wants to prepare the road in case that plan takes shape.

The team said construction should begin midsummer to late fall and that it’s currently working out maintenance costs with the city.

“There are a lot of competing interests,” said Tom Hoch, president and CEO of the Hennepin Theater Trust. “I think that’s the nature of placemaking and this is a big public space.”

The property owners are reflecting the interests of a variety of tenants within each building, he said, “and people are paying for this so they are even more interested, and understandably so. We aren’t going to do this every year. We all want this to be right and if it takes a little bit longer to do that, it is time well spent.”