 The Federal-Aid Highway Act of 1956 provided for 90 percent federal funding of highways that would become part of the Interstate Highway System, and the N.C. Highway Commission used the funds to build the rest of the highway, which opened as I-85 in 1958.The bridge, finished a year earlier, was "grandfathered" despite not meeting standards.Another section of I-85 opened to traffic on September 9, 1958 when an stretch in Mecklenburg County was opened.