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Bridge History

Before 1962, the only way to cross the St. Mary's River, between Sault Ste. Marie, Michigan and Sault Ste. Marie, Ontario, was by car ferry or by a railroad bridge built in 1880.

In 1935, the State Of Michigan created the International Bridge Authority (IBA), which gained Congressional approval in 1940 for an international crossing. In 1955, the Canadian Parliament created the St. Mary's River Bridge Company (SMRBC), giving it rights to construct an international crossing. In 1960, the SMRBC assigned its rights to the IBA.

Design and financing
The bridge was designed by Dr. Carl Gronquist of the consulting engineering firm Steinman, Boynton, Gronquist and Birdsall and cost $16 million to construct. The bridge was financed by two series of bonds:

  • Series A bonds totaling US $8.4 million were sold to private investors and paid off in 1983.
  • Series B bonds totaling US $7.85 million were bought by the Province of Ontario and were retired on September 1, 2000 from bridge revenues.

The Michigan State Highway Department agreed to construct the Michigan approach to the bridge, a project that cost approximately $4 million. Federal funds financed 90 percent of the approach, which is part of the interstate freeway system.

The International Bridge officially opened to traffic on October 31, 1962. For the next 38 years, the IBA operated both the U.S. and Canadian sides of the bridge, under the supervision of the Michigan Department of Transportation (MDOT). The IBA had three members from Michigan and two representatives from the SMRBC.

On September 1, 2000, the last of the bonds were retired. The State of Michigan and the Canadian Federal Government then agreed to create a new entity to manage and operate the bridge.

The Sault Ste. Marie Bridge Authority consists of four members appointed by the Governor of Michigan and four members appointed by the SMRBC. It is responsible for:

  • approving bridge tolls, operating budgets and business plans,
  • making rules for the use of the bridge and related properties,
  • approving property purchases and capital investments,
  • overseeing the investment of the bridge reserve fund.

The Sault Ste. Marie Bridge Authority assigns day-to-day responsibility for operating the bridge to the International Bridge Administration (IBA), a separate entity within MDOT. The IBA staff is composed of an equal number of Canadian and American residents.

The IBA carries out the business plans and budgets approved by the Sault Ste. Marie Bridge Authority. It performs the day-to-day operations needed to keep the bridge open to traffic twenty-four hours a day, year-round. These include toll collection, bridge maintenance, and capital improvements. The IBA provides a wide range of customer services necessary to ensure that people and goods move safely and smoothly between Michigan and Ontario.