In April, the Port Authority acquired the last of the properties that were in the path of the bridge's Manhattan approach. Plans for the Manhattan approach were approved by the New York City Board of Estimate around the same time. The approach was to consist of scenic, meandering ramps leading to both Riverside Drive and the Henry Hudson Parkway, which run along the eastern bank of the Hudson River at the bottom of the cliff in Washington Heights. The bridge would also connect to 178th and 179th Streets, at the top of Washington Heights. A third connection would be made to an underground highway running between and parallel to 178th and 179th Streets; this connection would become the 178th–179th Street Tunnels, and would later be replaced by the Trans-Manhattan Expressway. The original plan for the approach to the underground highway stated that the approach would be made using a monumental stone viaduct descending from the span at a 2.2% gradient. The Port Authority started evicting residents in the approach's path in October 1929. The same month, the Port Authority sold the final $30million in bonds to pay for the bridge.