Total bridges
116
Public highway bridges in St. Martin County
County profile · official public datasets
St. Martin County, LA
116 public highway bridges tracked in the FHWA National Bridge Inventory: 37.9% rated Good, 53.4% Fair, 8.6% Poor.
- 116
- Public bridges
- 37.9%
- Good condition
- 8.6%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
St. Martin County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 39%
- lowest Poor share in state
- 8.6%
- Poor-condition share
- 116
- public highway bridges
- 1980
- 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. Martin County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, St. Martin County ranks #25 of 64 Louisiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.6%). St. Martin County, Louisiana contains 116 public highway bridges. Roughly 37.9% are rated “Good,” 53.4% “Fair,” and 8.6% “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.
Good condition
37.9%
44 of 116 rated 7-9
Fair condition
53.4%
62 of 116 rated 5-6
Poor condition
8.6%
10 of 116 rated 4 or below
In-state Poor-share rank
#25 of 64
Among Louisiana counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 116 NBI-tracked bridges by lowest applicable component rating.
Good 37.9% (44)
Fair 53.4% (62)
Poor 8.6% (10)
St. Martin County's Poor-condition bridges carry 7,985 vehicle crossings a day
That is 1% of the county's reported daily bridge traffic on 8.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 799 crossings a day against 7,408 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 116 of 116 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
55.2% of St. Martin County's bridges have passed the 50-year mark
64 of the 116 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 37.9% 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 42.3% of the county's Poor-condition bridge traffic
LA0350 over BAYOU TECHE PARKS, built 1950, carries 3,378 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 10-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 7,985 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When St. Martin County's bridges were built
116 bridges with a recorded construction year, grouped by decade
- 1930s 1
1930–1939
1 bridges
- 1940s 2
1940–1949
2 bridges
- 1950s 8
1950–1959
8 bridges
- 1960s
1960–1969
24 bridges
- 1970s
1970–1979
38 bridges
- 1980s 9
1980–1989
9 bridges
- 1990s 8
1990–1999
8 bridges
- 2000s 10
2000–2009
10 bridges
- 2010s 7
2010–2019
7 bridges
- 2020s 9
2020–2029
9 bridges
What this shows Construction peaked in the 1970s, when 38 of the county's bridges still in the inventory were built, which is 32.8% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1980) matches the Louisiana average (1982).
How St. Martin County compares with Louisiana's closest counties by inventory size
The 5 Louisiana counties nearest St. Martin County in number of bridges, with their condition splits. Its 8.6% Poor share is the 4th-lowest of these 6. Its average build year of 1980 against a peer-group mean of 1980 is in line with the group.
Showing the 5 closest of 63 Louisiana counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Caldwell County | 124 | 57.3% | 34.7% | 8.1% | 1982 |
| St. Mary County | 124 | 31.5% | 62.1% | 6.5% | 1975 |
| Union County | 121 | 21.5% | 66.9% | 11.6% | 1977 |
| St. Martin County (this page) | 116 | 37.9% | 53.4% | 8.6% | 1980 |
| West Feliciana County | 108 | 47.2% | 33.3% | 19.4% | 1991 |
| Madison County | 104 | 16.3% | 76.9% | 6.7% | 1974 |
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. Martin 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. Martin County, both outside Louisiana so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside LA (116 bridges here).
- Howard County, AR · 116 bridges
- Cassia County, ID · 116 bridges
- Worth County, IA · 116 bridges
- Sheridan County, KS · 116 bridges
Similar average build year
Nearest mean year-built outside LA (1980 here).
- Tulsa County, OK · avg 1980 · 1,135 bridges
- Miami-Dade County, FL · avg 1980 · 1,057 bridges
- Pulaski County, AR · avg 1980 · 721 bridges
- McLennan County, TX · avg 1980 · 714 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (116)
E Stephenville Rd
GoodOver: COULEE
2.4 Mi NE of La 70, St. Martin, LA
Built 1986 Load: 45.0 t ADT: 422
LADY OF LAKE RD
GoodOver: CYPRESS ISLAND COULEE
1.6 Mi. W of La 31, St. Martin, LA
Built 1985 Load: 45.0 t ADT: 1,029
HAPPY TOWN ROAD
GoodOver: LITTLE ALABAMA BAYOU
SEC 111 T7S R8E, St. Martin, LA
Built 2001 Load: 46.3 t ADT: 30
I0010-E
GoodOver: LA 328
6.6 MI E OF US 167, St. Martin, LA
Built 2020 Load: 49.6 t ADT: 50,425
I0010-W
GoodOver: LA 328
5.3 MI W OF LA 347, St. Martin, LA
Built 2020 Load: 49.6 t ADT: 4,908
LA0737
GoodOver: Grand Canal 02
1.45 Mi W. of La 686, St. Martin, LA
Built 2023 Load: 56.1 t ADT: 575
LA0975
PoorOver: CREEK
4.3 MI N of I-10, St. Martin, LA
Built 1968 Load: 9.7 t ADT: 231
Boon Lasseigne Rd
PoorOver: Martin Bayou
2.2 Mi. E of La 347, St. Martin, LA
Built 1972 Load: 12.6 t ADT: 63
I0010
PoorOver: RAMP B. OFF RAMP
5.66 MI W of LA 975, St. Martin, LA
Built 1971 Load: 14.6 t ADT: 970
Auguillard Rd
PoorOver: COULEE
0.2 Mi. N. of La 347, St. Martin, LA
Built 1975 Load: 14.9 t ADT: 40
Division Rd
PoorOver: COULEE DU PORTAGE
0.2 Miles NE of LA 680, St. Martin, LA
Built 1965 Load: 15.4 t ADT: 129
LAKE FAUSSE ST PK
PoorOver: LAKE FAUSSE POINT
.16 MI S of Levee Rd, St. Martin, LA
Built 1980 Load: 15.6 t ADT: 66
LA0352
PoorOver: BAYOU AMY
2.0 MI EAST OF LA 349, St. Martin, LA
Built 1968 Load: 17.5 t ADT: 2,711
LA0975
PoorOver: CREEK
4.9 MI N of I-10, St. Martin, LA
Built 1968 Load: 17.5 t ADT: 231
LA0350
PoorOver: BAYOU TECHE PARKS
0.36 Mi NE of LA 31, St. Martin, LA
Built 1950 Load: 19.1 t ADT: 3,378
Ches Courville Rd
PoorOver: NICOLE COULEE
0.1 Mi. S of LA 352, St. Martin, LA
Built 1975 Load: 22.4 t ADT: 166
Read our methodology - how this data is sourced, computed, and verified.
Related
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.