County profile · official public datasets

Porter County, IN

277 public highway bridges tracked in the FHWA National Bridge Inventory: 42.6% rated Good, 52% Fair, 5.4% Poor.

277
Public bridges: 42.6%
Good condition: 5.4%
Poor condition

The verdict

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

Porter 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.

55th
of 92 on Poor share: 5.4%
Poor-condition share: 277
public highway bridges: 1970
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.

Porter County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Porter County ranks #55 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 5.4%). Porter County, Indiana contains 277 public highway bridges. Roughly 42.6% are rated “Good,” 52% “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

277

Public highway bridges in Porter County

Good condition

42.6%

118 of 277 rated 7-9

Fair condition

52%

144 of 277 rated 5-6

Poor condition

5.4%

15 of 277 rated 4 or below

In-state Poor-share rank

#55 of 92

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

Condition distribution

Share of 277 NBI-tracked bridges by lowest applicable component rating.

Good

42.6% (118)

Fair

52% (144)

Poor

5.4% (15)

Porter County's Poor-condition bridges carry 25,367 vehicle crossings a day

That is 1% 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 1,691 crossings a day against 11,027 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 277 of 277 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

63.5% of Porter County's bridges have passed the 50-year mark

176 of the 277 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 42.6% 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 20.2% of the county's Poor-condition bridge traffic

WAVERLY ROAD over LITTLE CALUMET RIVER, built 1966, carries 5,130 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 15-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 25,367 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

1
1920s

4
1930s

40
1940s

3
1950s

48
1960s

49
1970s

36
1980s

37
1990s

18
2000s

12
2010s

21
2020s

8

What this shows Construction peaked in the 1960s, when 49 of the county's bridges still in the inventory were built, which is 17.7% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1970, 8 years older than the Indiana average of 1978.

How Porter County compares with Indiana's closest counties by inventory size

The 5 Indiana counties nearest Porter County in number of bridges, with their condition splits. Its 5.4% Poor share is the 5th-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1978 is 8 years older.

Showing the 5 closest of 91 Indiana counties eligible for comparison.

Bridge inventory size and condition shares for Porter County and the 5 Indiana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Grant County	280	38.6%	59.6%	1.8%	1975
Vanderburgh County	279	47.7%	48%	4.3%	1980
Elkhart County	278	38.1%	55.8%	6.1%	1975
Delaware County	277	31.8%	62.8%	5.4%	1976
Porter County (this page)	277	42.6%	52%	5.4%	1970
Bartholomew County	269	53.5%	43.1%	3.3%	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 Porter 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 Porter County, both outside Indiana so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IN (277 bridges here).

Navajo County, AZ · 277 bridges
Shelby County, OH · 277 bridges
Florence County, SC · 277 bridges
Edgar County, IL · 278 bridges

Similar average build year

Nearest mean year-built outside IN (1970 here).

Hamilton County, OH · avg 1970 · 783 bridges
Yavapai County, AZ · avg 1970 · 543 bridges
Garfield County, OK · avg 1970 · 504 bridges
San Luis Obispo County, CA · avg 1970 · 401 bridges

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

All 277 Good 118 Fair 144 Poor 15

All bridges (277)

Sort:

Porter County Bridge Snapshot

Condition distribution

Porter County's Poor-condition bridges carry 25,367 vehicle crossings a day

63.5% of Porter County's bridges have passed the 50-year mark

One structure carries 20.2% of the county's Poor-condition bridge traffic

How Porter County compares with Indiana's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (277)

CR 300S

SR 8

CR 1000S

SR 8

CR 250W

SR 49 NB

CR 700E

CR 1300N

CR 750S

CR 150N

CR 500E

CR 500E

CR 325E

CR 200N

CR 500S

CR 450E

CR 500S

SR 49 SB

CR 100S

CR 600S

US 30

SR 49 SB

CR 1000S

CR 200W

SR 49 NB SR 2 EB

SR 49 SB SR 2 WB

SR 49

CR 100S

CR 875N

WEST STREET

CR 900S

SR 8

CR 200S

INDIAN BOUNDARY RD

MORGAN AVENUE

CR 200S

CR 700S

CR 625W

US 20

WAGNER ROAD

CR 700S

CR 900N

BRUMMITT ROAD

SMOKE ROAD

BROWN RD/CR 500 E

CR 500N

SR 49

US 6

CR 900S

CR 900S

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