The final elements on Columbia Island were constructed in 1939 and 1940. In April 1939, Congress approved $100,000 to build the last connections between the bridges and central traffic circle on the island, as well as build sidewalks, trails, and parking lots and to improve landscaping there. The CFA, after four years of deliberation, finally approved the lamppost design for the island in January 1940. The last major improvement to the island came in September 1940, when a "racetrack" feature – a larger outer traffic circle – was constructed to handle the rapidly increasing north–south traffic on the island. This permitted north–south motorists to avoid the bottleneck at the traffic circle (which now largely handled just east–west traffic).