US Bridges

Causeway SB over Lake Pontchartrain

Fair

St. Tammany Parish, Louisiana · Causeway Southbound · Structure no. 625230123900731

Built
1956
69 years old
Condition
Fair
inspected October 2024
Type
Movable - Bascule
Steel
Length
127,200 ft
1 main span
Daily traffic
18,830
1987 count
Owner
Toll Authority
Local Toll Authority

About this bridge

Causeway SB over Lake Pontchartrain is a steel movable - bascule carrying Causeway SB over Lake Pontchartrain in St. Tammany Parish, Louisiana. It was built in 1956, so it is 69 years old, older than the Louisiana average of 43 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 18,830 vehicles a day, projected to reach 20,713 by 2007. The structure is 127,200 ft (38,770.6 m) long and 31 ft wide. If it were closed, the detour would be 70.2 mi (113 km).

Location

Open in Google Maps
CarriesCauseway SB
CrossesLake Pontchartrain
LocationCauseway Southbound
RouteCounty Highway 0
CountySt. Tammany Parish
StateLouisiana
Coordinates30.36399, -90.09405
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38.6 US tons
Inventory rating32.5 US tons

Structure

Structure typeMovable - Bascule
MaterialSteel
DeckOpen grating
Main spans1 (+1500 approach)
Design loadHS 20
Structure length127,200 ft (38,770.6 m)
Longest span180 ft (54.9 m)
Deck width31 ft (9.6 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,830 (1987)
Projected traffic20,713 by 2007
Trucks—
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed70.2 mi (113 km)
TollToll bridge
National Highway SystemYes

Ownership and planned work

OwnerLocal Toll Authority
Maintained byLocal Toll Authority
Historic statusEligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$343.5 million
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Causeway SB over Lake Pontchartrain built?

It was built in 1956, making it 69 years old in 2025.

What condition is Causeway SB over Lake Pontchartrain in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in October 2024.

How much traffic does Causeway SB over Lake Pontchartrain carry?

About 18,830 vehicles per day (1987 count).

How long is Causeway SB over Lake Pontchartrain?

The structure is 127,200 ft (38,770.6 m) long with a longest span of 180 ft (54.9 m) and a deck 31 ft wide.

Who owns Causeway SB over Lake Pontchartrain?

It is owned by the Local Toll Authority.