County profile · official public datasets

Polk County, FL

360 public highway bridges tracked in the FHWA National Bridge Inventory: 55.3% rated Good, 44.7% Fair, 0% Poor.

360
Public bridges: 55.3%
Good condition: 0%
Poor condition

The verdict

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

Polk County posts a top-1% lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 1%
lowest Poor share in state: 0%
Poor-condition share: 360
public highway bridges: 1979
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.

Polk County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Polk County ranks #1 of 67 Florida counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 0%). Polk County, Florida contains 360 public highway bridges. Roughly 55.3% are rated “Good,” 44.7% “Fair,” and 0% “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

360

Public highway bridges in Polk County

Good condition

55.3%

199 of 360 rated 7-9

Fair condition

44.7%

161 of 360 rated 5-6

Poor condition

0 of 360 rated 4 or below

In-state Poor-share rank

#1 of 67

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

Condition distribution

Share of 360 NBI-tracked bridges by lowest applicable component rating.

Good

55.3% (199)

Fair

44.7% (161)

Poor

0% (0)

47.2% of Polk County's bridges have passed the 50-year mark

170 of the 360 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 55.3% 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.

1910s

1
1920s

7
1930s

10
1940s

23
1950s

27
1960s

83
1970s

26
1980s

18
1990s

89
2000s

38
2010s

28
2020s

10

What this shows Construction peaked in the 1990s, when 89 of the county's bridges still in the inventory were built, which is 24.7% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1979) matches the Florida average (1983).

How Polk County compares with Florida's closest counties by inventory size

The 5 Florida counties nearest Polk County in number of bridges, with their condition splits. Its 0% Poor share is the 1st-lowest of these 6. Its average build year of 1979 against a peer-group mean of 1983 is in line with the group.

Showing the 5 closest of 66 Florida counties eligible for comparison.

Bridge inventory size and condition shares for Polk County and the 5 Florida counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Pinellas County	435	63.7%	34.5%	1.8%	1983
Lee County	391	75.4%	23.8%	0.8%	1982
Collier County	370	73.2%	24.9%	1.9%	1981
Polk County (this page)	360	55.3%	44.7%	0%	1979
Sarasota County	298	57.7%	41.6%	0.7%	1982
Osceola County	255	62.4%	37.6%	0%	1985

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

Similar inventory size

Nearest county inventories outside FL (360 bridges here).

St. Tammany County, LA · 360 bridges
San Mateo County, CA · 361 bridges
Washita County, OK · 361 bridges
Richland County, SC · 361 bridges

Similar average build year

Nearest mean year-built outside FL (1979 here).

Pima County, AZ · avg 1979 · 1,150 bridges
Jefferson County, KY · avg 1979 · 662 bridges
Spartanburg County, SC · avg 1979 · 638 bridges
McPherson County, KS · avg 1979 · 586 bridges

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

All 360 Good 199 Fair 161 Poor 0

Good-condition bridges (199)

Sort:

Polk County Bridge Snapshot

Condition distribution

47.2% of Polk County's bridges have passed the 50-year mark

How Polk County compares with Florida'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 (199)

US-98 (SR-700)

SR 570 POLK WB 4.1

SR 570 POLK EB 4.1

SR 570 WB 10.8

SR-559

SHEPHERD RD.

CR 542 16.3

US-17 (US-92)

ALTURAS BABSON RD

SR 570 POLK 22.9

OLD COMBEE RD

GRIFFIN RD(CR-582)

US-17 NB (SR-35)

SR 570 POLK 17.1

SR 570 POLK 17.1

SR-546 (MEMORIAL)

BANANA ROAD

CR-559 (MAIN ST.)

NORTH FLORIDA AVE.

E.M. SMITH BLVD.

CR-35A W SOCRUM LP

SR 570 POLK WB 0.0

W LAKE HAMILTON RD

US-17 SB

US-17 NB

HELENA ROAD

WB I-4 OFF RAMP

GALLOWAY RD.

ROCKRIDGE ROAD

SWINDELL ROAD

WEST 10TH ST.

17th ST NORTHWEST

OLD BARTOW RD.

I-4 WB (SR-400)

CR-54 SB REGAN P

SR-542 (DUNDEE RD)

SR570 WB POLK 17.2

SR570 EB Polk 17.2

SR570 POLK RMP 0.1

US-92

SR-37 NB

SR 570 POLK WB 0.1

SR-37 SB

E. CALDWELL BLVD

I-4 EB (SR-400)

ROCKRIDGE ROAD

SR-60A (VAN FLEET)

E RAMP TO I-4

SR 570 POLK WB 8.7

SR 570 POLK 11.2

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