County profile · official public datasets

Moody County, SD

87 public highway bridges tracked in the FHWA National Bridge Inventory: 29.9% rated Good, 46% Fair, 24.1% Poor.

87
Public bridges: 29.9%
Good condition: 24.1%
Poor condition

The verdict

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

Moody County posts a higher-than-median Poor-condition share among rated counties in the state across rated county bridge inventory.

51st
of 66 on Poor share: 24.1%
Poor-condition share: 87
public highway bridges: 1973
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.

Moody County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Moody County ranks #51 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 24.1%). Moody County, South Dakota contains 87 public highway bridges. Roughly 29.9% are rated “Good,” 46% “Fair,” and 24.1% “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

Public highway bridges in Moody County

Good condition

29.9%

26 of 87 rated 7-9

Fair condition

46%

40 of 87 rated 5-6

Poor condition

24.1%

21 of 87 rated 4 or below

In-state Poor-share rank

#51 of 66

Among South Dakota counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 87 NBI-tracked bridges by lowest applicable component rating.

Good

29.9% (26)

Fair

46% (40)

Poor

24.1% (21)

Moody County's Poor-condition bridges carry 17,275 vehicle crossings a day

That is 9.9% of the county's reported daily bridge traffic on 24.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 823 crossings a day against 1,232 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 87 of 87 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

55.2% of Moody County's bridges have passed the 50-year mark

48 of the 87 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 29.9% 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 45.6% of the county's Poor-condition bridge traffic

I029 S over BIG SIOUX RV, built 1966, carries 7,880 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 21-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 17,275 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

3
1920s

4
1930s

2
1940s

2
1950s

6
1960s

31
1970s

8
1980s

6
1990s

8
2000s

7
2010s

6
2020s

4

What this shows Construction peaked in the 1960s, when 31 of the county's bridges still in the inventory were built, which is 35.6% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1973) matches the South Dakota average (1975).

How Moody County compares with South Dakota's closest counties by inventory size

The 5 South Dakota counties nearest Moody County in number of bridges, with their condition splits. Its 24.1% Poor share is the 5th-lowest of these 6. Its average build year of 1973 against a peer-group mean of 1978 is 5 years older.

Showing the 5 closest of 65 South Dakota counties eligible for comparison.

Bridge inventory size and condition shares for Moody County and the 5 South Dakota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Custer County	95	46.3%	48.4%	5.3%	1977
Clay County	94	58.5%	25.5%	16%	1985
Tripp County	90	27.8%	44.4%	27.8%	1975
Jackson County	89	29.2%	55.1%	15.7%	1969
Moody County (this page)	87	29.9%	46%	24.1%	1973
Fall River County	80	50%	42.5%	7.5%	1982

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 Moody 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 Moody County, both outside South Dakota so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside SD (87 bridges here).

Modoc County, CA · 87 bridges
Hendry County, FL · 87 bridges
Adams County, ID · 87 bridges
Humboldt County, IA · 87 bridges

Similar average build year

Nearest mean year-built outside SD (1973 here).

Jefferson County, AL · avg 1973 · 1,068 bridges
Erie County, NY · avg 1973 · 906 bridges
Davidson County, TN · avg 1973 · 832 bridges
Lancaster County, PA · avg 1973 · 801 bridges

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

All 87 Good 26 Fair 40 Poor 21

Good-condition bridges (26)

Sort:

Moody County Bridge Snapshot

Condition distribution

Moody County's Poor-condition bridges carry 17,275 vehicle crossings a day

55.2% of Moody County's bridges have passed the 50-year mark

One structure carries 45.6% of the county's Poor-condition bridge traffic

How Moody County compares with South Dakota's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Good-condition bridges (26)

474th Avenue

240th Street

480th Avenue

483rd Avenue

238th Street

477th Avenue

240th Street

485th Avenue

237th Street

487th Avenue

233rd Street

I029 N

478th Avenue

SD032

237th Street

478th Avenue

I029 S

241st Street

SD034

223rd Street

483rd Avenue

468th Avenue

SD034

SD034

SD034

SD034

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