The idea is to take the trucks going in and out of the Port of Miami off the bridge and surface streets and funnel them into a tunnel. However, that would cost more than $900 million.
There is $850 million in place, but the whole plan could fall through if city commissioners don't put in the final $50 million on Thursday.
No one thinks thousands of cargo trucks flooding downtown streets are good things, NBC 6's Nick Bogert reported.
They jam up traffic and intimidate drivers. They scare pedestrians, like Miami-Dade County college students.
"Sometimes the trucks get really close, really, really close to the sidewalk," one college student said.
"We lost a student a couple of years ago turning that corner," another student said. "A truck hit her right over there."
Truckers like Ali Salemmi also had complaints.
"It's tough going through downtown," he said. "It's a nightmare."
The proposed solution is to send trucks bound for the Port of Miami into a tunnel on Watson Island, under the cruise ship channel and to the port's cargo facilities.
Federal, state and county money is in place. Only $50 million from the city is missing.
A group of downtown businesspeople rallied for the tunnel. They bought television ad time, too, to urge Miami commissioners to approve the tunnel money on Thursday.
Greg Mirmelli, who owns a parking lot and other land in the area, said the port traffic is holding back downtown.
"Without the trucks, this area could be similar to midtown Manhattan," Mirmelli said. "The trucks coming through here will never let it be high-end."
City commissioners are under heavy pressure not to let the tunnel deal fall apart, Bogert reported.
The city manager, who is the only 'yes' vote for the tunnel out of five commissioners, said the other commissioners worry about where tunnel funds would come from.
"To believe it's a proper use of CRA or Community Redevelopment funds, (there are) lots of reservations for four of them?" Bogert asked.
"I would say so," Miami City Manager Pedro Hernandez said. "There are concerns."
CRA money is supposed to revitalize rundown neighborhoods, Bogert reported. Backers claimed that getting truck traffic off streets will allow for pedestrian-friendly business to sprout up near luxury condos along Biscayne Boulevard.
The cost of what backers claim is a better route to the port could be spread out over years and defrayed by tolls, Bogert said.
Some truckers said they were upset by that, while others were OK with it.
"The company and the customers have to pay for it," one trucker said. "Somebody's got to pay for it."
In the end, the fate of the tunnel may hinge less on public demonstrations than on closed-door negotiations between city and county, Bogert said.
The negotiations on Thursday will be about more than just the tunnel. They will include the performing arts center, museums in Bicentennial Park and a new ballpark for the Marlins.
City and county managers will try to find a package of agreements for the big dollar items that will pass both commissions.