Running through the heart of downtown
Boston, the existing Central Artery viaduct is being replaced with an 8-10 lane underground expressway, which shall (ostensibly) increase the flow of
traffic through the city (3000 years from now). The final portion of this
project will be to extend the new artery up and over the
Charles River, linking it to I-93, Route 1 (Tobin Bridge) and Storrow Drive.
This is the largest, most technically difficult and environmentally challenging infrastructure project ever undertaken in the United States (um, Panama Canal?), and is managed and operated by the Massachusetts Turnpike Authority. The project has two major components:
- The six-lane elevated highway will be replaced with an eight-to-ten-lane underground expressway directly beneath the existing road, culminating at its northern limit in a 14-lane, two-bridge crossing of the Charles River. When the underground highway is finished, the crumbling elevated road will be demolished and replaced by open space and modest development.
- I-90 (the Massachusetts Turnpike) will be extended from its current terminus south of downtown Boston through a tunnel beneath South Boston and Boston Harbor to Logan Airport. The first link in this new connection – the four-lane Ted Williams Tunnel under the harbor – was finished in December 1995.
The project spans 7.5 miles of highway, 161 lanes-miles in all, about half in tunnels. All told, the CA/T will place 3.8 million cubic yards of concrete – the equivalent of 2,350 acres, one foot thick – and excavate 13 million cubic yards of soil. The larger of the two Charles River bridges, a ten-lane cable-stayed bridge, will be the widest ever built and the first to use an asymmetrical design.
The Project also includes four major highway interchanges to connect the new roadways with the existing regional highway system.
The I-90 extension through South Boston to the Ted Williams Tunnel and Logan Airport will open in 2001. The northbound lanes of the underground highway replacing the elevated Central Artery open in 2002, the southbound lanes shortly thereafter in 2003. The entire project will be finished in 2004, including demolition of the elevated highway and restoration of the surface.
info from Mr. Tunnel and actual Central Artery/Third Harbor Tunnel website at www.bigdig.com. See The Big Dig. Of course, I don't live in Boston, so what the fuck do I know?