The Port of Miami Tunnel (POMT) has improved access to and from the Port of Miami, serving as a dedicated roadway connector linking the Port with the MacArthur Causeway and I-395. Previously the Port (located on an island in Biscayne Bay) was linked to the mainland only by the Port Bridge. The tunnel has improved access to the Port and traffic safety in downtown Miami by removing cargo trucks and cruise line buses from congested city streets, thereby facilitating ongoing and future development plans in and around downtown Miami. The project includes a tunnel under the Main Channel and related roadway work, including the widening of the MacArthur Causeway Bridge. Twin tubes, each 3,900 feet long and 41 feet in diameter, reach a depth of 120 feet below the water. The total capital cost of the project is $1,113 million.