By the midpoint of Schiro's mayoral administration, an accelerating number of building demolitions were approved and other projects were also being contemplated, such as the elevated Claiborne Expressway and Riverfront Expressway segments of I-10. Landrieu authorized the 1972 New Orleans Housing and Neighborhood Preservation Study. Most of that study's recommendations were enacted by Landrieu, including the 1976 establishment of the Historic District Landmarks Commission ("HDLC"), which extended design review and demolition controls for the first time to parts of New Orleans outside the French Quarter . In this period, Congress passed federal tax incentives favoring the rehabilitation of historic buildings. Combined with the founding of HDLC, New Orleans had hundreds of historic tax credit-subsidized redevelopment projects in the ensuing decades, representing hundreds of millions of dollars of new investment.