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The PortMiami Tunnel (also State Road 887; formerly ''Port of Miami Tunnel'') is a bored, undersea tunnel in Miami, Florida. It consists of two parallel tunnels (one in each direction) that travel beneath Biscayne Bay, connecting the MacArthur Causeway on Watson Island with PortMiami on Dodge Island. 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 31-year concession to operate the tunnel.〔 〕 The tunnel was first conceived in the 1980s as a way to remove traffic to PortMiami that was congesting downtown Miami streets. Prior to the tunnel's opening, the only route for PortMiami traffic was through the streets of downtown Miami; that traffic, especially trucks, was considered detrimental to the economic growth of downtown and a planned project to expand the port's capacity would increase the volume of trucks through downtown. Those 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. In the first month after opening, the tunnel averaged 7,000 vehicles per day; nearly 16,000 vehicles travel to the port each weekday.〔 The project was approved in December 2007, but was temporarily cancelled a year later. Construction began in May 2010. The tunnel boring machine began work in November 2011 and completed the second tunnel in May 2013.〔(【引用サイトリンク】title=Project History )〕 The tunnel was opened to traffic on August 3, 2014. ==History== Although a tunnel connecting the Port of Miami to Watson Island was first proposed in the 1980s, when the House rejected President Ronald Reagan's attempt to veto the bill to conduct a premilinary study and called it a "pork-barrel" project, when the port was only connected to the mainland by a two-lane drawbridge (the current six lane elevated bridge was built in the early 1990s), it was not until 2006 that the tender for the tunnel project was ready to be launched and December 2007 that the project was approved by City Commission. However, the economic crisis resulted in a cancellation of the project in December 2008 by one of the sponsors, Babcock & Brown, and the State of Florida.〔 〕 Despite this, in April 2009, following intense lobbying by Miami-Dade Mayor Carlos Alvarez, to avoid a new tender that would delay even further the start of construction, the project was reinstated. Port director Bill Johnson has also played a key role in supporting the Port of Miami infrastructure projects,〔 as well as developing a free-trade pact with Colombia. Altogether, the port infrastructure projects had an estimated cost of around two billion dollars. Prior to 2008, the project had been estimated at a total cost of $3.1 billion USD, however the revised project has an estimated cost of $1 billion USD (The difference in estimates partially due to differences in previous tunnel designs).〔 Financial closing on the project was reached in October, 2009. Miami-Dade County allegedly contributed $402 million, the city of Miami $50 million, and the state $650 million to build, operate and maintain it.〔 Those contributions are spread during construction and operation of the tunnel project. During construction, 90% of the funds are provided by the private sector. Of the estimated one billion dollar total project cost, 607 million it said to go to design and construction, 195.1 million to financing, 59.6 million to insurance and maintenance during construction, 41.2 million to reserves, and 209.8 million for state development cost.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Port Miami Tunnel」の詳細全文を読む スポンサード リンク
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