Lake Pontchartrain Causeway, or the
Causeway, consists of two
parallel bridges crossing Lake Pontchartrain in southern Louisiana.
The longer of the two bridges is either the
longest or second-longest in the world depending on definitions,
measuring at long. The Bang Na Expressway, a viaduct in Bangkok, is longer
at , but is excluded from most lists of longest bridges because it
crosses water for only a minimal portion of its
The bridges are supported by 9,500 concrete pilings. The two
bridges feature bascule
the navigation channel south of the north shore. The southern terminus
of the Causeway is in Metairie, Louisiana, a suburb of New Orleans. The northern terminus is at Mandeville,
The idea of a bridge spanning Lake Pontchartrain dates back to the
early 19th Century and Bernard de
, 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 homesites on the islands. The modern
Causeway started to take form in 1948 when the Louisiana
Legislature created what is now the Causeway Commission
The original Causeway was a two-lane span, measuring in length,
that opened in 1956
at a cost of $30.7 million.
A parallel two-lane span, 1/100th of a mile (15 m) longer than the
original, opened on May 10
at a cost of $26 million. The Causeway has always
been a toll bridge. Until 1999
, tolls were
collected from traffic going in each direction. To alleviate
congestion on the south shore, toll collections were eliminated on
the northbound span. The standard tolls for cars changed from $1.50
in each direction to a $3.00 toll collected on the North Shore for
southbound traffic only.
The opening of the Causeway boosted the fortunes of small North
Shore communities by reducing drive time into New Orleans by up to
50 minutes, bringing the North Shore into the New Orleans metropolitan area
the Causeway, residents of St. Tammany Parish had to go around the
lake, either the east side via the Rigolets Bridge on U.S.
Route 90 near Slidell, Louisiana or on the west side via U.S. Route 51
After Hurricane Katrina
August 29 2005
collected showed damage to the bridge, but the damage was mostly on
the unused turnaround on the older southbound span; the structural
foundations remained intact. The Causeways have never sustained
major damage of any sort due to hurricanes and other natural
occurrences, a rarity in the causeway community. The existing fiber
optic cable plant was blown out of the tray but remained intact per
optical time domain
(OTDR) analysis. With the I-10 Twin Span Bridge severely damaged, the Causeway was used as a major
route for recovery teams staying in highlands to the North to get
into New Orleans.
The Causeway reopened first to emergency
traffic and then to the general public, with tolls suspended, on
Tolls were reinstated by mid-October.
Pontchartrain Causeway is one of six highway spans in Louisiana that have a total length of or more.
others are, in order from longest to shortest, the Manchac Swamp bridge on I-55, the Atchafalaya Basin Bridge on I-10, the Bonnet Carré
Spillway bridge on I-10, the Chacahoula Swamp Bridge on U.S. 90, the Lake
Spans on I-10, and the Destrehan Swamp Bridge on I-310. The Maestri Bridge comes close, but runs short two tenths of a mile at
roughly in total length. In a few years the Leeville-Port
Fourchon Bridge on Louisiana
Highway 1 at over in total length will join this list.
is also home to the Norfolk Southern Lake Pontchartrain
bridge, which at is one of the longest railway bridges in
the United States.
It should be noted that the southern end of the Manchac Swamp
bridge is the western end of the Bonnet Carré Spillway bridge and
the northern end of the Destrehan Swamp bridge is the eastern end
of the Bonnet Carré Spillway bridge, so these three bridges by name
are in fact one contiguous bridge. The combined driving distance is
Major barge accidents
Heading north on the Causeway
The Causeway has been struck by barges on three occasions that have
caused structural damage resulting in the collapse of portions of
- January 17, 1960, an empty barge struck the bridge in heavy fog
in the morning. Two of the Causeway's spans collapsed and a third
was damaged. There were no fatalities.
- June 16, 1964, a tugboat pushing two barges collided with the
bridge in the early morning causing four spans to collapse into the
lake. A Continental
Trailways bus fell into the lake killing six people.
- August 1, 1974, several barges collided with the new northbound
span collapsing several spans and sending several vehicles into the
water, killing three people.
- Currently both spans have a speed limit during the day barring
fog, rain or high wind. This was increased from in 2004 in order to
increase safety on the span and reduce travel time by 4 minutes.
However, the southbound span has night time sight line problems at
the span's rises, requiring a speed limit of over the humps. The
Causeway Commission is studying the expense of lighting the rises
on the southbound and possibly the northbound span.
Third span plans
Heading south on the Causeway toward
In 2002, the Causeway Commission discussed the construction of a
third span before ultimately deciding to renovate the existing
spans as studies showed traffic growth leveling off. The third span
was estimated to have cost $400 million, which by 2006 had risen to
$800-900 million. In the aftermath of Hurricane Katrina, traffic
has grown to 40,000 vehicles per day as the population of North
Shore parishes have rapidly increased. A 1992 traffic study
predicted the traffic capacity of the current spans would be
exceeded in 2007; an estimate that was later revised to an earlier
date and rendered useless by Katrina related population
In early March 2006, General Manager Robert Lambert acknowledged
that the Commission may revisit the plan for a third span. Lambert
cited the increase in traffic and the need for better evacuations
routes to the north as the leading reasons for reexamining the need
for a new span. The proposed third span would be east of the
current northbound span and include two travel lanes and a full
right-hand shoulder. The current southbound span would also be
fitted with a full shoulder. The current northbound span would then
be used as a one lane with full shoulder reversible roadway to
correspond with peak travel hours.
- PILE RESTORATION OF THE LAKE PONTCHARTRAIN
- Hazardous crossings - Graphics - Times-Picayune -
- http://www.nola.com/newslogs/tpsttammany/ "Nighttime speed
limit going up on southbound Lake Pontchartrain Causeway"