It was built in a public–private partnership between three government entities—the Florida Department of Transportation, Miami-Dade County, and the City of Miami—and the private entity MAT Concessionaire LLC, which was in charge of designing, building, and financing the project and holds a 30-year concession to operate the tunnel.

Prior to the tunnel's opening, the only route for PortMiami traffic was a two-lane drawbridge that emptied out into the streets of downtown Miami.

The heavy traffic was considered detrimental to the economic growth of downtown, and a planned project to expand the port's capacity threatened to increase the volume of trucks coming through.

[9] The issues would be remedied by the construction of the tunnel, allowing traffic to move between PortMiami and the MacArthur Causeway (which connects to Interstate 95 via I-395) without traveling through downtown.

[13] Despite this, in April 2009, following intense lobbying by Miami-Dade Mayor Carlos Alvarez,[14] to avoid a new tender that would delay even further the start of construction, the project was reinstated.

Chosen due to their key involvement in the construction of the Channel Tunnel, a major tunnel in Europe, the selection of Bouygues was also met with controversy and protested by the Cuban exile community in Miami, due to the company's involvement with locally opposed construction projects in Cuba.

The tunnel will allow heavy trucks to bypass the congested Downtown Miami area, which is considered to be especially crucial with the large increase in trade traffic expected to be created by the Deep Dredge Project and the enlargement of the Panama Canal.

[27] Along with the related Deep Dredge and Panama Canal Expansion, over 30,000 jobs are expected to be created in the long run.

Ten banks, BNP Paribas, Banco Bilbao Vizcaya Argentaria, RBS Citizens, N.A., Banco Santander, Bayerische Hypo, Calyon, Dexia, ING Capital, Societe Generale, and WestLB, will provide the senior debt financing for the project,[19] which totals $341.5 million.

[30] The tunnel will be turned over to FDOT in first-class condition at the end of the contract in October 2044, thirty years after its completion.

According to the Miami Herald the financing structure of the plan is notable for the amount of financial risk taken by the builders in return for the long term concession on the tunnel.

[37][38] Some believe it may create traffic problems on the MacArthur Causeway; environmentalists worry about the potentially negative impact the construction could have on the Biscayne Bay.

[41] On July 19, the FDOT denied the request for more money to the contractor, stating that the geological issue cited was not as extensive as MAT claimed.

As for cargo traffic, truckers state that despite the longer miles, they can make more trips per day at Port Everglades.

[9] Port Everglades also has major redevelopment plans underway that includes its own deep dredging to a 50-foot (15 m) depth;[49] they also claim to have surpassed the Port of Miami, which has long been known as the "Cruise Capital of the World" as well as the "Cargo Gateway to the Americas," in both cruise traffic and cargo tonnage handled.

[54] Opposition to the railroad line returning to service included that it would be as much of a problem to downtown traffic as the container trucks and that the noise would be a disturbance to nearby residents.

[57] Another major benefit of the tunnel will be the redirecting of the large number of vehicles (nearly 16,000 daily; 2009 estimate),[58] many of them container trucks and cruise buses, that cross Biscayne Boulevard (US 1) at NW 5th Street (Port Boulevard), using level streets, such as Northeast 1st Avenue,[24] which for years were the only way to access the port.

[26] The developers for a once planned project for the north side of downtown, known as Miami City Square, stated that the heavy truck traffic and congestion in that area was a "grave concern.

"[60] The Omni Community Redevelopment Agency used a $50 million loan from Wachovia to donate towards financing the tunnel construction.

[63] It was estimated that 46% to 80% of the passenger vehicles, many of which are shuttle buses and taxis and make up nearly three quarters of the total port traffic will use the tunnel after it was completed.

[66] Currently, the largest cargo ships that dock at the port have a capacity of around 4,200 TEU's (Twenty-foot Equivalent Units).

The tunnel boring machine was built in Germany and had to be re-assembled in Florida after arriving in crates on the 168 metres (551 ft)[69] cargo ship Combi Dock 1[70] on Thursday, June 23, 2011,[71][72] and being assembled in the median of the causeway[73] where the construction is taking place.

Both directions of the MacArthur Causeway have remained open during the assembly of the machine except for nighttime lane closures and delays on the westbound side.

[74] The machine, which weighs more than 2,500 tons, was assembled in a 65-foot (20 m) deep pit known as the launching pad located in between two concrete walls in the median of the causeway, which only left a 42-foot (13 m) cutter visible from the road.

[13] The French firm Bouygues Construction has been put in charge of operating the tunnel boring machine, which was nicknamed "Harriet" in July 2011 after a naming competition was sponsored by MAT and the FDOT, and carried out by the Girl Scout Council of Tropical Florida.

In March 2011, one of the sub contractors of Bouygues fell under criticism for the dumping of tunnel fill on sensitive wetlands on Virginia Key.

[83] The intention was that they would be allowed to put 55,000 cubic yards (42,050.5 m3) of fill there provided that they use it to build a berm to block the view of Virginia Key's sewage water treatment plant.

[85] One other potential infill site that was briefly suggested is an inlet located between Bicentennial Park and the American Airlines Arena on the mainland in downtown, where Miami-Dade County was conducting a study on the effects it would have.