The bridge is a three-span cantilevered truss bridge at 1,525 ft in total length. The center span is longest at 800 ft and the maximum truss height is 115 ft. There are 36 approach spans to the North and 32 to the South. The roadway is seven lanes wide between the shortest span and the center to accommodate the now-unused toll plaza. The Northbound toll plaza was closed in the 1980s; the Southbound toll plaza was closed on July 21, 2014.
History
The bridge was originally operated by the Mystic River Bridge Authority. The bridge, according to the statute enacted May 23, 1946, would be turned over to the Massachusetts Department of Public Works once the $27 million in bonds used to finance the bridge's construction was retired. The bridge would then become part of the state highway system to be maintained and operated by the department free of tolls. Operation of the bridge was turned over to the new Massachusetts Port Authority in 1956. Instead of eliminating the tolls, the tolls were increased to 25 cents to cover the closing of the Northbound toll plaza in the 1980s. Starting in the early 1990s the tolls increased sharply to help pay for the Big Dig. As of October 28, 2016, the toll is $1.55 for non-commercial cars traveling in either direction. In 1967, the Mystic River Bridge was renamed in honor of Maurice J. Tobin, former Boston mayor and Massachusetts governor. Construction of the bridge began during his term as governor. Tobin went on to serve as Secretary of Labor under President Harry Truman before he died in 1953. In 1973, a gravel truck traveling over the lower deck crashed into a support, collapsing the upper deck onto the truck and killing the driver. Later that year, the bridge reopened after more than two months of repair. On January 4, 1990, racial hoaxer and double murderer Charles Stuartcommitted suicide by leaping from the bridge. Legislation was passed to transfer the bridge from Massport to the new Massachusetts Department of Transportation, effective January 1, 2010. On the morning of July 21, 2014, the bridge's tollbooths were closed and eventually removed for an all-electronic and cashless tolling system, and from that point on all toll charges are paid for via either E-ZPass at the current rate, or "pay-by-mail" where an invoice will be sent to motorists’ homes via license plate number recognition at the former cash toll rate. This inaugurated a 2½ year process by MassDOT which converted all of the toll roads and bridges throughout the Commonwealth to automatic open road tolling.
Restorations
In September 2017, the Massachusetts Department of Transportation announced a three-year $41.6 million project to restore the bridge deck, steel repairs, and painting a portion of the bridge. The first phase of work will start in April 2018 and run through November 2018 and will be conducted again during the months of April - November for the next two years, ending in 2020. The work will be done by J. F. White Contracting Co.
