PortMiami Tunnel

The PortMiami Tunnel provides greatly improved access to Miami’s seaport through a new tunnel under Biscayne Bay. 



  • Miami, Florida, USA


  • Florida Department of Transportation

Project Status

  • Completed in 2014


  • 2014 Project of the Year, American Society of Civil Engineers
  • 2015 America’s Transportation Award
  • Outstanding Technical Achievement Award, Miami Chapter, Florida Engineering Society

Improving Access to Miami’s Port

The PortMiami Tunnel, which opened in August 2014, provides motorists with greatly improved access to Miami’s seaport, the largest and busiest cruise ship terminal in the world. The tunnel also removes 1.5 million trucks annually from downtown Miami streets, relieving congestion and improving air quality. The PortMiami Tunnel was Florida's first public-private partnership (P3). It was delivered via a design-build-finance-operate-maintain contract. The tunnel was constructed by the Miami Access Tunnel (MAT) Consortium on behalf of FDOT, the City of Miami, and Miami-Dade County. MAT, as concessionaire, will operate and maintain the tunnel for 30 years. WSP USA served as owner's representative to the Florida Department of Transportation (FDOT) for the $1.3 billion project. Our responsibilities included project management, civil and structural concept design, final design review, tunnel engineering, cost estimating and scheduling, environmental assessment, and preparation of public-private partnership procurement documents. We also supported FDOT during the contract negotiation process, and provided construction engineering and inspection services to FDOT under a separate contract.



Key Numbers

Length of Tunnel
.75 miles .75 miles
Number of tunnels
2 2

Project Poses Challenges

The new tunnel and related highway improvements reroute port traffic along Interstate 395 over the MacArthur Causeway Bridge to Watson Island, and then through the 3/4-mile-long, twin-bore tunnel under Biscayne Bay to Dodge Island and the port. Trucks and cruise passengers, including travelers en route to and from Miami International Airport, can now bypass downtown streets entirely.  

To accommodate the increased traffic volume, the MacArthur Causeway Bridge was widened to eight lanes (four in each direction), and the causeway itself – a major interstate highway – was relocated along with other local roads to make room for the tunnel entrance on Watson Island.

The scope of the project also included construction of two operational buildings and a maintenance facility, roadway access improvements for tunnel traffic, bridge and road improvements on Dodge Island (including construction of 1,200 feet of additional railroad track), extensive utility relocation work, construction of deep wells for drainage, lighting for Watson and Dodge islands, traffic signals, signage, and pavement markings.

The PortMiami Tunnel is the first bored roadway tunnel ever constructed in South Florida’s complex sedimentary geology. To date, it is the largest-diameter bored soft ground completed tunnel in the U.S.

The project team overcame significant challenges, including a major grouting problem beneath Biscayne Bay, construction in a coastal, hurricane-prone environment; design requirements to resist 500-year storm events; and restrictions that construction could not interfere with cruise and cargo traffic or the native manatee or corals in Biscayne Bay, which is a state-designated aquatic preserve.