Before the existence of the Westbank Expressway, the only highway traversing the west bank communities between US 90 and Algiers was former State Route 30, a narrow two-lane highway that zigzagged through the center of each town. This route is now generally followed by the modern LA 18, which was created in the 1955 Louisiana Highway renumbering. During the 1930s, this once rural area was transformed into a booming industrial corridor focused along the Mississippi River and the Harvey Canal, which had become a link in the Gulf Intracoastal Waterway. By 1942, the existing highway had become heavily congested, and the draw bridge crossing of the Harvey Canal was specifically cited as one of the worst traffic bottlenecks in the entire state. That year, the Jefferson Parish Police Jury and a committee of local citizens began to lobby the state highway department to alleviate the problem by constructing a new four-lane highway parallel to the existing Route 30. The proposed bypass would extend from US 90 near the Huey P. Long Bridge to the Algiers Naval Station. It would also feature a bridge across the Harvey Canal with a higher draw span, allowing most marine traffic to pass underneath without impeding the flow of vehicular traffic.
