Total bridges
143
Public highway bridges in Turner County
County profile · official public datasets
Turner County, SD
143 public highway bridges tracked in the FHWA National Bridge Inventory: 38.5% rated Good, 35.7% Fair, 25.9% Poor.
- 143
- Public bridges
- 38.5%
- Good condition
- 25.9%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Turner County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.
- 55th
- of 66 on Poor share
- 25.9%
- Poor-condition share
- 143
- public highway bridges
- 1984
- 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.
Turner County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Turner County ranks #55 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 25.9%). Turner County, South Dakota contains 143 public highway bridges. Roughly 38.5% are rated “Good,” 35.7% “Fair,” and 25.9% “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
38.5%
55 of 143 rated 7-9
Fair condition
35.7%
51 of 143 rated 5-6
Poor condition
25.9%
37 of 143 rated 4 or below
In-state Poor-share rank
#55 of 66
Among South Dakota counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 143 NBI-tracked bridges by lowest applicable component rating.
Good 38.5% (55)
Fair 35.7% (51)
Poor 25.9% (37)
Turner County's Poor-condition bridges carry 4,094 vehicle crossings a day
That is 7.8% of the county's reported daily bridge traffic on 25.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 111 crossings a day against 647 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 143 of 143 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
35.7% of Turner County's bridges have passed the 50-year mark
51 of the 143 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 38.5% 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 18.5% of the county's Poor-condition bridge traffic
45520 275 ST over WEST FORK VERMILLION RV, built 1952, carries 758 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 37-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 4,094 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Turner County's bridges were built
143 bridges with a recorded construction year, grouped by decade
- 1910s 4
1910–1919
4 bridges
- 1930s 5
1930–1939
5 bridges
- 1940s 9
1940–1949
9 bridges
- 1950s
1950–1959
12 bridges
- 1960s
1960–1969
15 bridges
- 1970s 10
1970–1979
10 bridges
- 1980s
1980–1989
13 bridges
- 1990s
1990–1999
28 bridges
- 2000s
2000–2009
20 bridges
- 2010s
2010–2019
23 bridges
- 2020s 4
2020–2029
4 bridges
What this shows Construction peaked in the 1990s, when 28 of the county's bridges still in the inventory were built, which is 19.6% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year is 1984, 9 years newer than the South Dakota average of 1975.
How Turner County compares with South Dakota's closest counties by inventory size
The 5 South Dakota counties nearest Turner County in number of bridges, with their condition splits. Its 25.9% Poor share is the 4th-lowest of these 6. Its average build year of 1984 against a peer-group mean of 1968 is 16 years newer.
Showing the 5 closest of 65 South Dakota counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Roberts County | 157 | 22.9% | 52.9% | 24.2% | 1970 |
| Beadle County | 152 | 19.1% | 47.4% | 33.6% | 1955 |
| Butte County | 143 | 30.8% | 57.3% | 11.9% | 1976 |
| Turner County (this page) | 143 | 38.5% | 35.7% | 25.9% | 1984 |
| Lawrence County | 136 | 36% | 51.5% | 12.5% | 1980 |
| Bon Homme County | 126 | 21.4% | 50.8% | 27.8% | 1961 |
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 Turner 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 Turner County, both outside South Dakota so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside SD (143 bridges here).
- Franklin County, AR · 143 bridges
- San Francisco County, CA · 143 bridges
- Woodson County, KS · 143 bridges
- Adair County, KY · 143 bridges
Similar average build year
Nearest mean year-built outside SD (1984 here).
- Hennepin County, MN · avg 1984 · 936 bridges
- Duval County, FL · avg 1984 · 831 bridges
- El Paso County, CO · avg 1984 · 686 bridges
- Bell County, TX · avg 1984 · 660 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Good-condition bridges (55)
SD019
GoodOver: CK
2.8 N JCT SD 44 WEST, Turner, SD
Built 1999 Load: 56.2 t ADT: 1,660
45660 284 ST.
GoodOver: CK
0.5S & 0.6E HURLEY, Turner, SD
Built 2014 Load: 60.7 t ADT: 50
291ST STREET
GoodOver: TURKEY CK
8.8W VIBORG, Turner, SD
Built 2008 Load: 99.9 t ADT: 140
SD019
GoodOver: CK
4.3 S JCT US 18 WEST, Turner, SD
Built 1963 Load: 99.9 t ADT: 1,358
45770 275 ST
GoodOver: ELCE CK
4.7E PARKER, Turner, SD
Built 2014 Load: 99.9 t ADT: 743
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.