Structure 625230123900731 · St. Tammany County, LA
Carries Causeway SB over Lake Pontchartrain, Causeway Southbound.
Set by its lowest-rated component: Superstructure and Substructure at 6 of 9.
How ratings work127,200 ft end to end: about 353 football fields, or 24.1 miles. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a bascule bridge (drawn closed).
| State | Louisiana |
| County | St. Tammany |
| Location | Causeway Southbound |
| Carries | Causeway SB |
| Crosses | Lake Pontchartrain |
| Coordinates | 30.36399, -90.09405 |
| Material | Steel |
| Design | Movable - Bascule |
| Total Length | 127200.1 ft (38770.6 m) |
| Max Span | 180.1 ft (54.9 m) |
| Deck Width | 31.5 ft (9.6 m) |
| Deck Area | 372197.8 sq m |
| Main Spans | 1 |
| Year Built | 1956 |
| Avg Daily Traffic | 18,830 (1987) |
| Lanes On Bridge | 2 |
| Last Inspection | October 2024 |
| Inspection Frequency | Every 24 months |
| Owner | Local Toll Authority |
| Historical Significance | Bridge is eligible for the National Register |
| Scour Critical | Unknown |
| Structure Number | 625230123900731 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.