Lake Pontchartrain Causeway

Lake Pontchartrain Causeway
The southern end of the causeway at Metairie, Louisiana in 1998
Carries	4 lanes of Causeway Blvd
Crosses	Lake Pontchartrain
Locale	Metairie and Mandeville, Louisiana, U.S.A.
Maintained by	Greater New Orleans Expressway Commission
Characteristics
Design	Low-level trestle with mid-span bascule
Total length	23.87 mi (38.442 km)
Clearance above	15 ft
History
Opened	August 30, 1956 (southbound) May 10, 1969 (northbound)
Statistics
Daily traffic	43,000
Toll	$3.00 (southbound)

The Lake Pontchartrain Causeway, sometimes only the Causeway, is a causeway composed of two parallel bridges crossing Lake Pontchartrain in southern Louisiana, United States. The longer of the two bridges is 23.83 miles (38.35 km) long. The southern terminus of the Causeway is in Metairie, Louisiana, a suburb of New Orleans. The northern terminus is at Mandeville, Louisiana.

Since 1969, it was listed by Guinness World Records as the longest bridge over water in the world; in 2011 in response to the opening of the allegedly longer Jiaozhou Bay Bridge in China, Guinness created two categories for bridges over water: continuous and aggregate lengths over water. Lake Pontchartrain Causeway then became the longest bridge over water (continuous) while Jiaozhou Bay Bridge the longest bridge over water (aggregate).

The bridges are supported by 9,500 concrete pilings. The two bridges feature a bascule, which spans the navigation channel 8 miles (13 km) south of the north shore.

The idea of a bridge spanning Lake Pontchartrain dates back to the early 19th century and Bernard de Marigny, the founder of Mandeville. He started a ferry service that continued to operate into the mid-1930s. In the 1920s, a proposal called for the creation of artificial islands that would then be linked by a series of bridges. The financing for this plan would come from selling home sites on the islands. The modern Causeway started to take form in 1948 when Ernest M. Loeb Jr. envisioned the project. Due to his lobbying and vision, the Louisiana Legislature created what is now the Causeway Commission. The Louisiana Bridge Company was formed to construct the bridge, which in turn appointed James E. Walters Sr. to direct the project.