County profile · official public datasets

St. Louis County, MO

912 public highway bridges tracked in the FHWA National Bridge Inventory: 29.9% rated Good, 64.7% Fair, 5.4% Poor.

912
Public bridges
29.9%
Good condition
5.4%
Poor condition

The verdict

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

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

Top 23%
lowest Poor share in state
5.4%
Poor-condition share
912
public highway bridges
1987
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. Louis County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, St. Louis County ranks #26 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 5.4%). St. Louis County, Missouri contains 912 public highway bridges. Roughly 29.9% are rated “Good,” 64.7% “Fair,” and 5.4% “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

912

Public highway bridges in St. Louis County

Good condition

29.9%

273 of 912 rated 7-9

Fair condition

64.7%

590 of 912 rated 5-6

Poor condition

5.4%

49 of 912 rated 4 or below

In-state Poor-share rank

#26 of 115

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

Condition distribution

Share of 912 NBI-tracked bridges by lowest applicable component rating.

Good
29.9% (273)
Fair
64.7% (590)
Poor
5.4% (49)

St. Louis County's Poor-condition bridges carry 1,056,872 vehicle crossings a day

That is 5.3% of the county's reported daily bridge traffic on 5.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 21,569 crossings a day against 14,905 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 912 of 912 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

29.7% of St. Louis County's bridges have passed the 50-year mark

271 of the 912 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 17.8% of the county's Poor-condition bridge traffic

IS 270 E over CST CONWAY RD, built 1964, carries 188,530 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 49-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,056,872 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When St. Louis County's bridges were built

912 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 2000s, when 184 of the county's bridges still in the inventory were built, which is 20.2% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year is 1987, 8 years newer than the Missouri average of 1979.

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

How St. Louis County compares with Missouri's closest counties by inventory size

The 5 Missouri counties nearest St. Louis County in number of bridges, with their condition splits. Its 5.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1987 against a peer-group mean of 1978 is 9 years newer.

Showing the 5 closest of 114 Missouri counties eligible for comparison.

Bridge inventory size and condition shares for St. Louis County and the 5 Missouri counties closest to it in inventory size
County Bridges Poor
Jackson County 930 5.4%
St. Louis County (this page) 912 5.4%
Greene County 493 5.3%
Johnson County 476 4.4%
Jasper County 471 11%
Clay County 436 6.9%

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. Louis 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. Louis County, both outside Missouri so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside MO (912 bridges here).

Similar average build year

Nearest mean year-built outside MO (1987 here).

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

All 912 Good 273 Fair 590 Poor 49

Good-condition bridges (273)

LACKLAND RD

Good

Over: E TRIB OF FEE FEE

S 26 T 46 N R 5 E, St. Louis, MO

Built 2018 Load: 66.6 t ADT: 5,192

CLAYCHESTER DR

Good

Over: TWO MILE CR

S 26 T 45 N R 5 E, St. Louis, MO

Built 2014 Load: 68.4 t ADT: 950

OLD HALLS FERRY RD

Good

Over: HALLS FERRY CR

S 32 T 47 N R 7 E, St. Louis, MO

Built 2018 Load: 69.3 t ADT: 10,330

RP IS170W TO IS270

Good

Over: RP IS270E TO NORTH HANLE

S 939 T 47 N R 6 E, St. Louis, MO

Built 2002 Load: 70.2 t ADT: 21,814

BEMISTON AVE-RMP D

Good

Over: FOREST PARK PKWY

S 15 T 45 N R 6 E, St. Louis, MO

Built 2005 Load: 70.2 t ADT: 1,322

BARRETT STATION RD

Good

Over: UP RR

S 9 T 44 N R 5 E, St. Louis, MO

Built 2004 Load: 71.1 t ADT: 1,435

RIVER CITY CASINO

Good

Over: UP RR

S 19 T 44 N R 6 E, St. Louis, MO

Built 2009 Load: 71.1 t ADT: 8,029

BRAESHIRE DR

Good

Over: BR GRAND GLAIZE CR

S 31 T 45 N R 5 W, St. Louis, MO

Built 2008 Load: 72.9 t ADT: 3,095

VON TALGE RD

Good

Over: BR OF MATTESE CR

S 33 T 44 N R 6 E, St. Louis, MO

Built 1990 Load: 74.7 t ADT: 3,196

WEIDMAN RD

Good

Over: GRAND GLAIZE CR

S 31 T 45 N R 5 E, St. Louis, MO

Built 2001 Load: 74.7 t ADT: 4,626

FOREST PARK PKWY E

Good

Over: BRENTWOOD BLVD

S 15 T 45 N R 6 E, St. Louis, MO

Built 2005 Load: 74.7 t ADT: 20,527

FOREST PARK PKWY W

Good

Over: BRENTWOOD BLVD

S 16 T 45 N R 6 E, St. Louis, MO

Built 2005 Load: 74.7 t ADT: 16,983

NE LUCAS-HUNT RD

Good

Over: NS RR

S 18 T 46 N R 7 E, St. Louis, MO

Built 1941 Load: 76.5 t ADT: 7,737

WOODSON RD

Good

Over: RVR DES PERES

S 32 T 46 N R 6 E, St. Louis, MO

Built 2009 Load: 76.5 t ADT: 8,563

OLD HALLS FERRY RD

Good

Over: COLD WATER CR

S 13 T 47 N R 6 E, St. Louis, MO

Built 2005 Load: 81.9 t ADT: 5,663

WILD HORSE CR RD

Good

Over: CHESTERFIELD CR

S 4 T 45 N R 4 E, St. Louis, MO

Built 2007 Load: 89.1 t ADT: 7,807

WILSON AVE

Good

Over: WILSON CR TRIB

S 16 T 45 N R 4 E, St. Louis, MO

Built 2018 Load: 90.0 t ADT: 1,798

IS 64 E

Good

Over: METROLINK

S 21 T 45 N R 6 E, St. Louis, MO

Built 2008 Load: 92.7 t ADT: 151,691

BAUMGARTNER RD

Good

Over: BR OF MATTESE CR

S 15 T 43 N R 6 E, St. Louis, MO

Built 1982 Load: 99.9 t ADT: 12,499

MERAMEC BOTTOM RD

Good

Over: MERAMEC RVR TRIB

S 17 T 43 N R 6 E, St. Louis, MO

Built 2000 Load: 99.9 t ADT: 19,169

MERAMEC BOTTOM

Good

Over: MERAMEC RVR TRIB

S 17 T 43 N R 6 E, St. Louis, MO

Built 2000 Load: 99.9 t ADT: 3,396

BIG BEND RD

Good

Over: TRIB TO FISHPOT CR

S 11 T 44 N R 4 E, St. Louis, MO

Built 2008 Load: 99.9 t ADT: 27,120

BAXTER RD

Good

Over: CREVE COEUR CR

S 22 T 45 N R 4 E, St. Louis, MO

Built 2012 Load: 99.9 t ADT: 14,233

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.