STILLWATER (AP) -- A transportation study says charging a toll to cross the new St. Croix River bridge could pay for half its construction costs and cover future maintenance expenses.

The Minnesota Department of Transportation says motorists could expect to pay $3 to cross the bridge linking the state with Wisconsin near Stillwater. MnDOT estimates the bridge will cost $642 million if construction starts in 2013 and is completed in three years. The study says toll collections could be electronic using the MnPASS transponder system.

A new bridge would replace the Stillwater Lift Bridge built in 1931. About 19,000 vehicles cross the two-lane lift bridge each day.

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