The original 23.86-mile-long Lake Pontchartrain Causeway Bridge structure, which now carries southbound traffic, was designed by the firm of Palmer & Baker. When it opened in 1956, it was the longest bridge in the world by more than 15 miles. Built in just fourteen months, it used assembly-line, mass-production methods for the first time in bridge construction. The bridge was designed to use hundreds of identical hollow concrete pilings, concrete caps, and pre-stressed deck sections manufactured at an on-shore facility and barged into place. Engineering News-Record called the project "a bold venture requiring unusual foresight, ingenuity and resourcefulness."