County profile · official public datasets

Cook County, IL

1,721 public highway bridges tracked in the FHWA National Bridge Inventory: 28.8% rated Good, 57.5% Fair, 13.8% Poor.

1,721
Public bridges: 28.8%
Good condition: 13.8%
Poor condition

The verdict

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

Cook County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

88th
of 102 on Poor share: 13.8%
Poor-condition share: 1,721
public highway bridges: 1969
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.

Cook County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Cook County ranks #88 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 13.8%). Cook County, Illinois contains 1,721 public highway bridges. Roughly 28.8% are rated “Good,” 57.5% “Fair,” and 13.8% “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

1,721

Public highway bridges in Cook County

Good condition

28.8%

495 of 1,721 rated 7-9

Fair condition

57.5%

989 of 1,721 rated 5-6

Poor condition

13.8%

237 of 1,721 rated 4 or below

In-state Poor-share rank

#88 of 102

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

Condition distribution

Share of 1,721 NBI-tracked bridges by lowest applicable component rating.

Good

28.8% (495)

Fair

57.5% (989)

Poor

13.8% (237)

Cook County's Poor-condition bridges carry 5,864,125 vehicle crossings a day

That is 10% of the county's reported daily bridge traffic on 13.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 24,743 crossings a day against 30,089 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 1,714 of 1,721 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

65.7% of Cook County's bridges have passed the 50-year mark

1,130 of the 1,721 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 28.8% 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 4.4% of the county's Poor-condition bridge traffic

I- 90 94 RYAN ELEV over CANAL TO STEWART STS, built 1962, carries 256,900 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 237-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 5,864,125 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

2
1900s

28
1910s

20
1920s

99
1930s

107
1940s

66
1950s

446
1960s

315
1970s

71
1980s

90
1990s

150
2000s

145
2010s

144
2020s

38

What this shows Construction peaked in the 1950s, when 446 of the county's bridges still in the inventory were built, which is 25.9% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year is 1969, 10 years older than the Illinois average of 1979.

How Cook County compares with Illinois's closest counties by inventory size

The 5 Illinois counties nearest Cook County in number of bridges, with their condition splits. Its 13.8% Poor share is the 5th-lowest of these 6. Its average build year of 1969 against a peer-group mean of 1981 is 12 years older.

Showing the 5 closest of 101 Illinois counties eligible for comparison.

Bridge inventory size and condition shares for Cook County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Cook County (this page)	1,721	28.8%	57.5%	13.8%	1969
Champaign County	727	58.9%	32.5%	8.7%	1982
Will County	649	43.1%	46.4%	10.5%	1983
McLean County	624	60.9%	36.2%	2.9%	1981
Livingston County	579	51.8%	39.9%	8.3%	1978
Iroquois County	570	46.5%	39.1%	14.4%	1980

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

Similar inventory size

Nearest county inventories outside IL (1,721 bridges here).

San Diego County, CA · 1,632 bridges
Travis County, TX · 1,544 bridges
San Bernardino County, CA · 1,422 bridges
Sedgwick County, KS · 1,333 bridges

Similar average build year

Nearest mean year-built outside IL (1969 here).

Fresno County, CA · avg 1969 · 916 bridges
Cuyahoga County, OH · avg 1969 · 871 bridges
Ventura County, CA · avg 1969 · 501 bridges
Somerset County, PA · avg 1969 · 454 bridges

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

All 1,721 Good 495 Fair 989 Poor 237

Fair-condition bridges (989)

Sort:

Cook County Bridge Snapshot

Condition distribution

Cook County's Poor-condition bridges carry 5,864,125 vehicle crossings a day

65.7% of Cook County's bridges have passed the 50-year mark

One structure carries 4.4% of the county's Poor-condition bridge traffic

How Cook County compares with Illinois's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (989)

143RD STREET

ASHLAND AVE

CANAL ST

DAMEN AVE

W MONROE ST

N WELLS ST

ADDISON ST

CAMPBELL

NORMAL AVE

EGGLESTON AVE

PULASKI ROAD

PULASKI RD

CLARK ST

WESTERN BLVD

N HALSTED ST

WABASH AVE

MONROE ST

Jackson Dr

PARK DRIVE

LAKE SHORE DRIVE

W TAYLOR ST

Commerce Drive

FULLERTON PARKWAY

Homan Avenue

LOIS DR

I-90 SKYWAY

I-90 SKYWAY

I-90 SKYWAY

I-90 SKYWAY

I-90 SKYWAY

STONY ISL SB TO E

LASALLE DR

WELLS ST

NORMAL AVE

EGGLESTON AVENUE

WASHINGTON ST

ROOSEVELT ROAD

ROOSEVELT ROAD

ROOSEVELT ROAD

ROOSEVELT RD

CONGRESS PARKWAY(S

CONGRESS PARKWAY(N

BALBO DRIVE

JACKSON BOULEVARD

NORTH DAMEN AVENUE

NORTH AVE

LARAMIE AVE

Mallard Lane

LATHROP AVE.

CENTRAL AV

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