A New England intra-regional highway, Interstate 93 serves the Boston metropolitan area, northern Massachusetts through Lawrence, the state of New Hampshire, and the Northeast Kingdom of Vermont. The freeway provides a direct connection to Canada in conjunction with Interstate 91 north of St. Johnsbury, Vermont.
Built as part of the Big Dig project, the Thomas P. O’Neill, Jr. Tunnel carries 1.5 miles of Interstate 93 below central Boston. Opened in 2003, the tunnel runs between Kneeland and Causeway Streets, directly linking with the Leonard P. Zakim Bunker Hill Bridge.
Through the White Mountains and Franconia Notch in northern New Hampshire, Interstate 93 transitions into a parkway, with a reduced right-of-way and two or three lane sections. Nine miles long, Franconia Notch Parkway runs between Exit 33 (U.S. 3 north of Lincoln) and Exit 35 (NH 18 near Echo Lake). This exception to Interstate standards allows the freeway to intrude minimally on the sensitive areas of the Notch, including the former Old Man of the Mountain, which collapsed on May 3, 2003. Recreational areas are accessible along this stretch at Exits 34A, 34B and 34C.
Interstate 93 through Downtown Boston was reconstructed in one of the most expensive and dramatic projects in highway history. Known as “The Big Dig,” this megaproject resulted in the removal of the Fitzgerald Expressway, the elevated “green elephant” through Downtown (though part of the double deck in Charlestown remains). Traffic was relocated to a system of tunnels, as well as a new ten lane (six lanes northbound, four lanes southbound) cable-stayed Leonard P. Zakim Bridge over the Charles River, plus the four lane Leverett Circle Connector bridge. This new span replaced the original six lane double decker bridge.
No ceremonies were held as the last section of new freeway for Interstate 93 opened to traffic. The December 20, 2003 completion of the southbound lanes through the tunnel system marked the end of the $14.6 billion project. Often controversial, the project was $4 billion over budget, and the source of bitterness among residents and politicians alike. With origins in 1987, the Big Dig even raised concerns of then President Ronald Reagan because of its overwhelming cost. Nonetheless, after years of construction, the two mile system of underground roadways built during the Big Dig resulted in the removal of a city eyesore and traffic nightmare.1
With the removal of the Fitzgerald Expressway, one and half miles of green space was created within its former footprint. This resulted in eight acres of public park space and additional land made available for new housing, shops and cultural venues. Collectively 7.5 miles long, all in all 16 million cubic yards of dirt were excavated for the new tunnel system.1
Unfortunately, the Big Dig had a lasting legacy. Its underwater tunnels had a tendency to leak and the project managers (Bechtel and Parsons Brinckerhoff) were accused of making decisions that resulted in extraordinary costs for the project. Cost overruns led NBC News to refer to this project repeatedly on its “Fleecing of America” segment. The Boston Globe provides more detailed information on the Big Dig in the “Big Dig Report.”
The northern portion of Interstate 93 in New Hampshire, from Plymouth to the Vermont state line, travels through the picturesque White Mountains. The section that runs along Franconia Notch Parkway is technically not a part of I-93, as it does not meet full Interstate standards. The parkway design was the result of a compromise between the park service and highway department. Maintained as a limited access highway, side access along the parkway is restricted to interchanges and designated parking areas.
When originally constructed, Franconia Notch Parkway used a separate exit numbering system from the rest of Interstate 93. According to Jeffrey Moss this changed in 2002 when Exits 1, 2 and 3 were renumbered to confirm with the rest of I-93. Aside from brown guide signs and the narrowing of the freeway, the transition to Franconia Notch Parkway along Interstate 93 is nearly invisible to the motoring public, so a separate exit number system made little sense.
Interstate 93 primarily bypasses communities along U.S. 3 in Massachusetts and New Hampshire. Where the freeway turns westward toward Vermont at Littleton, it briefly parallels U.S. 302. U.S. 2 accompanies the northernmost reaches of the freeway corridor through the town of St. Johnsbury.
The first portion of Interstate 93 constructed in Massachusetts extended 24 miles north from Medford to the New Hampshire state line. Costing $47 million, work ran from 1956 to 1963. Delays ensued on the three mile link southward to the Northeast Expressway (then Interstate 95) due to the relocation of residents and businesses along the corridor. It eventually opened in 1973, around the same time that plans for I-95 within the Route 128 beltway (Yankee Division Highway) were dropped.5
The Massachusetts Department of Public Works requested a spate of changes to the Interstate Highway system in and around Boston in letters to the Federal Highway Administration (FHWA) sent on August 20 and September 10, 1974. These changes were previously incorporated in the comprehensive transportation proposals for the Greater Boston Region approved by the state on May 23, 1974. The revised route descriptions eliminated Interstate 695, the planned inner loop in Boston, realigned I-95 and extended I-93:
The 6.7-mile segment of State Route 128 from the junction of I-95 in Canton generally easterly to a junction with the Southeast Expressway (State Route 3) in Braintree was added as part of Route I-93 under the provisions of 23 U.S.C. 139(a). The 8.5-mile segment of the Southeast Expressway (State Route 3) northerly from Braintree to the Central Artery in Boston was added as part of I-93 under the provisions of 23 U.S.C. 103(e)(2).
The 36.9-mile segment of State Route 128 from a junction with existing I-95 and State Route 128 in Canton northwesterly, northerly, and easterly via Neeham, Waltham, and Burlington to a junction with existing I-95 in Peabody was added as part of Route I-95 under the provisions of 23 U.S.C. 139(a).
This resulted in an extension of Interstate 93 southward along both the John F. Fitzgerald and Southeast Expressways to Braintree and west along the Yankee Division Highway to I-95 at Canton. The American Association of State Highway and Transportation Officials (AASHTO) endorsed the extension south from the Boston/Somerville city limits to Route 128 in Braintree on June 17, 1975, and the extension west along Route 128 on November 15, 1975.