County profile · official public datasets

St. Tammany County, LA

360 public highway bridges tracked in the FHWA National Bridge Inventory: 33.3% rated Good, 60.6% Fair, 6.1% Poor.

360
Public bridges
33.3%
Good condition
6.1%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

St. Tammany County pairs a top-quartile lowest Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 14%
lowest Poor share in state
6.1%
Poor-condition share
360
public highway bridges
1976
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

St. Tammany County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, St. Tammany County ranks #9 of 64 Louisiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.1%). St. Tammany County, Louisiana contains 360 public highway bridges. Roughly 33.3% are rated “Good,” 60.6% “Fair,” and 6.1% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

Total bridges

360

Public highway bridges in St. Tammany County

Good condition

33.3%

120 of 360 rated 7-9

Fair condition

60.6%

218 of 360 rated 5-6

Poor condition

6.1%

22 of 360 rated 4 or below

In-state Poor-share rank

#9 of 64

Among Louisiana counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 360 NBI-tracked bridges by lowest applicable component rating.

Good
33.3% (120)
Fair
60.6% (218)
Poor
6.1% (22)

St. Tammany County's Poor-condition bridges carry 73,574 vehicle crossings a day

That is 1.6% of the county's reported daily bridge traffic on 6.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,504 crossings a day against 12,276 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 342 of 360 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

50% of St. Tammany County's bridges have passed the 50-year mark

180 of the 360 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 33.3% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 39.3% of the county's Poor-condition bridge traffic

US0190 over US190B/LA21/Bouge Falaya, built 1958, carries 28,900 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 22-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 73,574 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When St. Tammany County's bridges were built

360 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 103 of the county's bridges still in the inventory were built, which is 28.6% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1976, 6 years older than the Louisiana average of 1982.

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How St. Tammany County compares with Louisiana's closest counties by inventory size

The 5 Louisiana counties nearest St. Tammany County in number of bridges, with their condition splits. Its 6.1% Poor share is the 2nd-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1983 is 7 years older.

Showing the 5 closest of 63 Louisiana counties eligible for comparison.

Bridge inventory size and condition shares for St. Tammany County and the 5 Louisiana counties closest to it in inventory size
County Bridges Poor
Orleans County 382 9.9%
Jefferson County 379 4.5%
St. Tammany County (this page) 360 6.1%
Vernon County 341 7.6%
Ouachita County 337 12.8%
Lafayette County 322 7.8%

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to St. Tammany County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for St. Tammany County, both outside Louisiana so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside LA (360 bridges here).

Similar average build year

Nearest mean year-built outside LA (1976 here).

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 360 Good 120 Fair 218 Poor 22

Good-condition bridges (120)

US0190

Good

Over: DRAINAGE

0.9 M W OF I-10, St. Tammany, LA

Built 1970 Load: 32.4 t ADT: 20,256

I0012

Good

Over: I-12 OVER US 11

I0012, St. Tammany, LA

Built 1970 Load: 32.7 t ADT: 29,236

I0012

Good

Over: I-12 OVER I-59 NB

I0012, St. Tammany, LA

Built 1970 Load: 33.6 t ADT: 29,236

US0190-B

Good

Over: INTERSTATE 10

1.85 MILES EAST OF JCT US, St. Tammany, LA

Built 2008 Load: 33.7 t ADT: 2,496

Watercross Pkwy

Good

Over: Drain

0.1 Mi N of Ochsner Blvd, St. Tammany, LA

Built 2013 Load: 34.0 t ADT: 400

I10 SW Frontage Rd

Good

Over: CANAL

1 MI. SOUTH OF US 190, St. Tammany, LA

Built 2012 Load: 34.3 t ADT: 200

US0190

Good

Over: ABITA RIVER

2.1 MILES NORTH OF I-12, St. Tammany, LA

Built 1975 Load: 34.5 t ADT: 14,668

US0190

Good

Over: LA 22

2.4 Mi S of I-12, St. Tammany, LA

Built 1981 Load: 34.5 t ADT: 66,360

LA0021

Good

Over: WRIGHTS CREEK

LA0021, St. Tammany, LA

Built 1975 Load: 34.5 t ADT: 8,257

LA1088

Good

Over: I 12

3.4 Mi NE of LA 59, St. Tammany, LA

Built 2011 Load: 35.0 t ADT: 12,029

US0190

Good

Over: DRAIN

0.2 MILE WEST OF US 90, St. Tammany, LA

Built 2013 Load: 35.0 t ADT: 2,496

I0012

Good

Over: CANAL&BIKE TRAIL

0.2 M W OF LA 59, St. Tammany, LA

Built 1976 Load: 35.3 t ADT: 29,236

MONROE ST W OFF RP

Good

Over: N. CAUSEWAY APPR. S BOUN

0.60 MI N OF CAUSEWAY BR., St. Tammany, LA

Built 1993 Load: 35.3 t ADT: 1,600

Dummyline Rd

Good

Over: BAYOU DEZAIRE

0.4 M WEST OF LA 1077, St. Tammany, LA

Built 1990 Load: 35.3 t ADT: 1,563

LA0021

Good

Over: BOGUE CHITTO RIVER

LA0021, St. Tammany, LA

Built 1974 Load: 35.4 t ADT: 8,257

LA0021

Good

Over: BOGUE CHITTO RIVER

LA0021, St. Tammany, LA

Built 1974 Load: 35.4 t ADT: 7,481

LA0040

Good

Over: DRAIN

0.6 M E OF LA 25, St. Tammany, LA

Built 1979 Load: 35.4 t ADT: 3,689

LA0021

Good

Over: BOGUE CHITTO RV. RELIEF

0.9 M N OF LA 41, St. Tammany, LA

Built 1975 Load: 36.3 t ADT: 8,257

LA0040

Good

Over: DRAIN

0.9 M E OF LA 25, St. Tammany, LA

Built 1978 Load: 36.3 t ADT: 3,689

Bob Levy Rd

Good

Over: TALISHEEK CREEK BRIDGE

LA 435-N ON BOB LEAVY RD, St. Tammany, LA

Built 1985 Load: 36.6 t ADT: 60

Hidden Oaks Dr

Good

Over: CREEK

0.5 MILES NORTH OF GAUSE, St. Tammany, LA

Built 2012 Load: 36.9 t ADT: 100

LA0021

Good

Over: WRIGHTS CREEK

LA0021, St. Tammany, LA

Built 1975 Load: 37.2 t ADT: 7,481

Fitzgerald Church

Good

Over: SIMULSA CREEK

1.1 MILES NORTH OF MILLIO, St. Tammany, LA

Built 2012 Load: 37.3 t ADT: 198

W CSWY APPR E.B.

Good

Over: CHINCHUB BAYOU

1.6 MI S LA 22 W CAUSEWAY, St. Tammany, LA

Built 1954 Load: 37.3 t ADT: 8,000

LA 22 W CAUSEWAY

Good

Over: W CSWY OV CHINCHUB BAYOU

1.6 MI S LA 22 W CAUSEWAY, St. Tammany, LA

Built 1954 Load: 37.3 t ADT: 8,000

W. 28th ave.

Good

Over: MILE BRANCH

1.0 MILES NORTH OF NORTH, St. Tammany, LA

Built 2007 Load: 38.1 t ADT: 350

US0190

Good

Over: PONCHITOLAWA CR

US 190, St. Tammany, LA

Built 1976 Load: 38.1 t ADT: 4,708

LA0021

Good

Over: BOGUE CHITTO RV RELIEF

0.9 M N OF LA 41, St. Tammany, LA

Built 1975 Load: 38.1 t ADT: 7,481

I0012

Good

Over: BAYOU LACOMBE

0.3 M W OF LA 434, St. Tammany, LA

Built 1976 Load: 38.1 t ADT: 79,502

I0012

Good

Over: BAYOU LACOMBE

0.3 M W OF LA 434, St. Tammany, LA

Built 1976 Load: 38.1 t ADT: 29,236

LA0040

Good

Over: TCHEFUNCTE RIVER

3.9 Mi E of LA 445, St. Tammany, LA

Built 2023 Load: 38.2 t ADT: 2,778

US0190

Good

Over: FRENCH BRANCH

0.3 MILES WEST OF US 190, St. Tammany, LA

Built 2013 Load: 38.9 t ADT: 2,496

US0190

Good

Over: CREEK

0.3 M SW OF LA 25, St. Tammany, LA

Built 1969 Load: 38.9 t ADT: 12,522

I0012

Good

Over: DONYA ST/CANAL

I0012, St. Tammany, LA

Built 1970 Load: 39.0 t ADT: 78,215

I0012

Good

Over: I-12 OVER PAR RD ROLLINS

0.9 M W OF US 11, St. Tammany, LA

Built 1970 Load: 39.0 t ADT: 29,236

I0012

Good

Over: EAST BEDICO CREEK

I0012, St. Tammany, LA

Built 1975 Load: 39.9 t ADT: 53,386

I0012

Good

Over: I-12 OVER I-10

I0010, St. Tammany, LA

Built 1970 Load: 39.9 t ADT: 78,215

AVE LOUIS QUATROZE

Good

Over: PIPE AT CREEK

.9 MI W US 190-VERSAILLES, St. Tammany, LA

Built 1996 Load: 39.9 t ADT: 300

INDEPENDENCE AVE

Good

Over: CANAL

ON INDEPENDENCE AVENUE 0., St. Tammany, LA

Built 2016 Load: 40.5 t ADT: 1,000

Million Dollar Rd

Good

Over: BOGUE FALAYA RIVER REL

0.2 MILES EAST OF LA 25, St. Tammany, LA

Built 1990 Load: 40.5 t ADT: 1,768

I0012

Good

Over: BAYOU LIBERTY

I0012, St. Tammany, LA

Built 1972 Load: 40.8 t ADT: 78,365

I0012

Good

Over: BAYOU LIBERTY

I0012, St. Tammany, LA

Built 1972 Load: 40.8 t ADT: 29,236

LA0435

Good

Over: DRAIN

4.29 MILES EAST OF LA 36, St. Tammany, LA

Built 2010 Load: 41.5 t ADT: 4,200

LA0435

Good

Over: ABITA CREEK

4.40 MILES EAST OF LA 36, St. Tammany, LA

Built 2010 Load: 41.5 t ADT: 4,200

Amber St

Good

Over: BRIDGE OVER FRENCH BRANC

N. OF 190 AMBER ST. LM 10, St. Tammany, LA

Built 2001 Load: 41.5 t ADT: 550

W. 19th Ave

Good

Over: DRAINAGE CANAL

0.6 MILES SOUTH OF US 190, St. Tammany, LA

Built 2011 Load: 41.7 t ADT: 400

LA0041

Good

Over: TALISHEEK CREEK

0.4 M NW OF LA 435, St. Tammany, LA

Built 1972 Load: 42.6 t ADT: 3,043

LA1082

Good

Over: LITTLE BOGUE FALAYA RIV

0.2 M N OF LA 21, St. Tammany, LA

Built 1972 Load: 42.6 t ADT: 2,916

LA0021

Good

Over: TCHEFUNCTE RIVER

1.85 MI. N OF I-12, St. Tammany, LA

Built 2017 Load: 43.4 t ADT: 34,242

LA0021

Good

Over: TCHEFUNCTE RIVER

2.0 MILES NORTH OF I-12 J, St. Tammany, LA

Built 2016 Load: 43.4 t ADT: 12,029

Read our methodology - how this data is sourced, computed, and verified.

Related

Browse all → | Rankings →
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.