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.

Total bridges

116

Public highway bridges in St. Martin County

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

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).

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

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.

Bridge inventory size and condition shares for St. Martin County and the 5 Louisiana counties closest to it in inventory size
County Bridges Poor
Caldwell County 124 8.1%
St. Mary County 124 6.5%
Union County 121 11.6%
St. Martin County (this page) 116 8.6%
West Feliciana County 108 19.4%
Madison County 104 6.7%

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).

Similar average build year

Nearest mean year-built outside LA (1980 here).

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

All bridges (116)

Bayou Mercier Rd.

Fair

Over: BERARD CANAL BAYOU

0.2 Mi. W of LA 96, St. Martin, LA

Built 1965 Load: 13.6 t ADT: 414

LA3361

Fair

Over: TECHE BAYOU

0.1 Mi. E of LA 31, St. Martin, LA

Built 1951 Load: 14.5 t ADT: 6,798

Zin Zin Rd

Fair

Over: COULEE

0.7 Mi. S of LA 349, St. Martin, LA

Built 1966 Load: 15.2 t ADT: 658

Adam Guidry Rd

Fair

Over: COULEE

0.2 Mi. SW of LA 686, St. Martin, LA

Built 1968 Load: 15.2 t ADT: 160

LA0321

Fair

Over: CREEK

0.71 MI S OF LA 347, St. Martin, LA

Built 1966 Load: 15.4 t ADT: 1,732

Grand Bois Rd

Fair

Over: COULEE

1.8 Mi. E. of La 3039, St. Martin, LA

Built 1967 Load: 16.5 t ADT: 140

Hughes Rd

Fair

Over: LASALLE COULEE

0.4 Mi.E of US 90, St. Martin, LA

Built 1970 Load: 17.2 t ADT: 144

Huval St

Fair

Over: TRUE CANAL

0.4 Mi N of LA 352, St. Martin, LA

Built 1967 Load: 17.2 t ADT: 208

Duchamp Rd

Fair

Over: LASALLE COULEE

1.1 Mi. NE of La 182, St. Martin, LA

Built 1966 Load: 17.8 t ADT: 1,388

Patin St.

Fair

Over: TRUE CANAL

0.4 Mi. N of LA 352, St. Martin, LA

Built 1967 Load: 17.8 t ADT: 128

Orphe Guidry Rd.

Fair

Over: GRAND CANAL

1.4 Mi NE of LA 686, St. Martin, LA

Built 1969 Load: 17.8 t ADT: 149

Lee Gordon Rd.

Fair

Over: GRAND CANAL

1.5 Mi. NE of LA 686, St. Martin, LA

Built 1970 Load: 17.8 t ADT: 132

LA0345

Fair

Over: Coulee DU Portage

2.7 MI SOUTH OF LA 96, St. Martin, LA

Built 1962 Load: 18.1 t ADT: 1,319

LA0345

Fair

Over: Point Claire Coulee

2.4 MI SOUTH OF LA 96, St. Martin, LA

Built 1962 Load: 18.1 t ADT: 1,319

CYPRESS ISLAND RD

Fair

Over: CREEK

1.3 MI SW of LA 31, St. Martin, LA

Built 1962 Load: 18.1 t ADT: 1,584

McVeigh Rd

Fair

Over: Pont Brule Bayou

3.1 Mi. W of LA 31, St. Martin, LA

Built 1975 Load: 18.1 t ADT: 36

Roman Robin Rd

Fair

Over: NICOLE COULEE

0.7 Mi. S of LA 352, St. Martin, LA

Built 1955 Load: 18.5 t ADT: 263

Johnson Rd

Fair

Over: DUMOLIN CANAL

0.8 Mi. N. of LA 678, St. Martin, LA

Built 1970 Load: 18.8 t ADT: 226

Johnson Rd

Fair

Over: DUMOLIN CANAL

1.2 Mi. N. of LA 678, St. Martin, LA

Built 1970 Load: 18.8 t ADT: 226

LA3039

Fair

Over: BAYOU PORTAGE

5.7 MI NORTH OF LA 347, St. Martin, LA

Built 1961 Load: 19.3 t ADT: 1,807

Division Rd

Fair

Over: COULEE

1.0 Mi SW of LA 345, St. Martin, LA

Built 1970 Load: 19.3 t ADT: 129

LA0341

Fair

Over: COULEE DATIDER

0.93 MI NORTH OF LA 31, St. Martin, LA

Built 1964 Load: 19.8 t ADT: 2,152

Poche Bridge Rd

Fair

Over: TECHE BAYOU

0.08 Mi S of LA 31, St. Martin, LA

Built 1974 Load: 19.8 t ADT: 4,252

LA0096

Fair

Over: BAYOU TECHE ST M.

0.13 MI EAST OF LA 31, St. Martin, LA

Built 1942 Load: 20.0 t ADT: 8,684

LA3083

Fair

Over: C COTEAU HOLMES

1.07 MI WEST OF LA 679, St. Martin, LA

Built 1967 Load: 20.1 t ADT: 1,360

LA3083

Fair

Over: C COTEAU HOLMES

1.80 MI East OF LA 679, St. Martin, LA

Built 1967 Load: 20.1 t ADT: 1,360

LA0031

Fair

Over: DAIGRE CANAL

1.5 MI N of LA 86, St. Martin, LA

Built 1950 Load: 20.9 t ADT: 4,367

LA0031

Fair

Over: DRAINAGE CANAL

1.79 MI N OF LA 1.79, St. Martin, LA

Built 1957 Load: 21.1 t ADT: 3,996

LA0737

Fair

Over: GRAND CANAL 02

0.16 MI EAST OF LA 686, St. Martin, LA

Built 1973 Load: 21.7 t ADT: 575

Section 28 Rd

Fair

Over: MARTIN BAYOU

1.6 MI E of LA 3039, St. Martin, LA

Built 2003 Load: 21.7 t ADT: 608

E Stephenville Rd

Fair

Over: MILHOMME BAYOU

1.4 Mi NE of La 70, St. Martin, LA

Built 2001 Load: 22.4 t ADT: 756

LA0093

Fair

Over: BAYOU FUSELIER

3.1 MI W OF LA 31, St. Martin, LA

Built 1959 Load: 22.7 t ADT: 3,987

Jeff Deblanc Pkwy

Fair

Over: TECHE BAYOU

0.4 MI E of LA 31, St. Martin, LA

Built 2001 Load: 23.0 t ADT: 3,818

LA0353

Fair

Over: BAYOU VERMILION

1.6 MI SOUTH OF LA 94, St. Martin, LA

Built 1976 Load: 23.6 t ADT: 3,749

Division Rd

Fair

Over: COULEE

0.4 Mi. SW of LA 345, St. Martin, LA

Built 1970 Load: 23.6 t ADT: 129

LA0355

Fair

Over: Bayou Teche

0.16 MI W OF LA 347, St. Martin, LA

Built 1949 Load: 24.9 t ADT: 4,721

Bordelon Rd

Fair

Over: I-10

1.5 MI WEST OF LA 347, St. Martin, LA

Built 1970 Load: 25.4 t ADT: 2,970

LA0353

Fair

Over: BAYOU CAPUCIN

5.1 MI SOUTH OF LA 94, St. Martin, LA

Built 1976 Load: 26.2 t ADT: 3,749

LA0353

Fair

Over: CYPRESS ISLAND BAYOU

1.9 MI NORTH OF LA 31, St. Martin, LA

Built 1962 Load: 27.2 t ADT: 4,152

LA0094

Fair

Over: VERMILION RIVER

1.0 MI E OF LA 353, St. Martin, LA

Built 1954 Load: 29.9 t ADT: 18,293

I0010

Fair

Over: W ATCHAFALAYA FLOODWAY

2.5 MI EAST OF LA 347, St. Martin, LA

Built 1971 Load: 30.8 t ADT: 37,370

I0010

Fair

Over: W ATCHAFALAYA FLOODWAY

4.47 Mi W of LA 3177, St. Martin, LA

Built 1971 Load: 30.8 t ADT: 1,585

Sawmill Rd.

Fair

Over: COULEE DATIDER

1.3 Mi. W of LA 341, St. Martin, LA

Built 1975 Load: 31.1 t ADT: 1,100

LA0092

Fair

Over: TECHE BAYOU

0.49 MI E OF LA 31, St. Martin, LA

Built 1984 Load: 31.8 t ADT: 4,071

I0010

Fair

Over: RAMP A. ON RAMP

0.37 Mi W of LA 3177, St. Martin, LA

Built 1971 Load: 31.8 t ADT: 970

I0010

Fair

Over: RAMP D. ON RAMP

4.8 MI EAST OF LA 347, St. Martin, LA

Built 1971 Load: 31.8 t ADT: 970

Potato Shed Rd

Fair

Over: BAYOU BERARD DRAIN CANAL

0.8 MI. E. OF HWY LA 678, St. Martin, LA

Built 1985 Load: 32.1 t ADT: 186

US0090

Fair

Over: CREEK

0.73 MI SOUTH OF LA 96, St. Martin, LA

Built 1965 Load: 32.4 t ADT: 62,432

I0010

Fair

Over: DRAIN

5 Mi E of LA 328, St. Martin, LA

Built 1968 Load: 32.4 t ADT: 5,704

LA0031

Fair

Over: LA 31 OVER I-10

1.17 MI N OF LA 94, St. Martin, LA

Built 1970 Load: 32.7 t ADT: 8,168
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.