County profile · official public datasets

Miami-Dade County, FL

1,057 public highway bridges tracked in the FHWA National Bridge Inventory: 69.5% rated Good, 25.7% Fair, 4.7% Poor.

Compiled by PlainBridges

1,057
Public bridges: 69.5%
Good condition: 4.7%
Poor condition

The verdict

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

Miami-Dade County posts a higher-than-median Poor-condition share among rated counties in the state across large county bridge inventory.

48th
of 67 on Poor share: 4.7%
Poor-condition share: 1,057
public highway bridges: 1980
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.

Miami-Dade County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Miami-Dade County ranks #48 of 67 Florida counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.7%). Miami-Dade County, Florida contains 1,057 public highway bridges. Roughly 69.5% are rated “Good,” 25.7% “Fair,” and 4.7% “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

1,057

Public highway bridges in Miami-Dade County

Good condition

69.5%

735 of 1,057 rated 7-9

Fair condition

25.7%

272 of 1,057 rated 5-6

Poor condition

4.7%

50 of 1,057 rated 4 or below

In-state Poor-share rank

#48 of 67

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

Condition distribution

Share of 1,057 NBI-tracked bridges by lowest applicable component rating.

Good

69.5% (735)

Fair

25.7% (272)

Poor

4.7% (50)

Miami-Dade County's Poor-condition bridges carry 637,295 vehicle crossings a day

That is 1.6% of the county's reported daily bridge traffic on 4.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 13,006 crossings a day against 42,986 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 1,045 of 1,057 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

57.3% of Miami-Dade County's bridges have passed the 50-year mark

606 of the 1,057 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 69.5% 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 7.6% of the county's Poor-condition bridge traffic

WB NW 25th St. over North Line Canal, built 2016, carries 48,400 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 50-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 637,295 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

1
1920s

21
1930s

7
1940s

23
1950s

75
1960s

310
1970s

200
1980s

80
1990s

73
2000s

104
2010s

129
2020s

34

What this shows Construction peaked in the 1960s, when 310 of the county's bridges still in the inventory were built, which is 29.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1980) matches the Florida average (1983).

How Miami-Dade County compares with Florida's closest counties by inventory size

The 5 Florida counties nearest Miami-Dade County in number of bridges, with their condition splits. Its 4.7% Poor share is the 6th-lowest of these 6. Its average build year of 1980 against a peer-group mean of 1987 is 7 years older.

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

Bridge inventory size and condition shares for Miami-Dade County and the 5 Florida counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Miami-Dade County (this page)	1,057	69.5%	25.7%	4.7%	1980
Orange County	885	75.6%	24.3%	0.1%	1998
Hillsborough County	840	68.8%	31%	0.2%	1985
Duval County	831	63.7%	34.5%	1.8%	1984
Broward County	686	69.2%	28.9%	1.9%	1982
Palm Beach County	610	79.7%	20%	0.3%	1987

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

Similar inventory size

Nearest county inventories outside FL (1,057 bridges here).

Jefferson County, AL · 1,068 bridges
Shelby County, TN · 1,077 bridges
Wayne County, MI · 1,026 bridges
Worcester County, MA · 1,014 bridges

Similar average build year

Nearest mean year-built outside FL (1980 here).

Tulsa County, OK · avg 1980 · 1,135 bridges
Pulaski County, AR · avg 1980 · 721 bridges
McLennan County, TX · avg 1980 · 714 bridges
Hinds County, MS · avg 1980 · 663 bridges

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

All 1,057 Good 735 Fair 272 Poor 50

All bridges (1,057)

Sort:

Miami-Dade County Bridge Snapshot

Condition distribution

Miami-Dade County's Poor-condition bridges carry 637,295 vehicle crossings a day

57.3% of Miami-Dade County's bridges have passed the 50-year mark

One structure carries 7.6% of the county's Poor-condition bridge traffic

How Miami-Dade 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

All bridges (1,057)

SR 836 EB

NW 122 ST(W 68 ST)

NW186 ST(SR860) WB

NW186 ST(SR860) EB

SR860 WB (870624)

COMP SR-860

SR821 SB HEFT 18.4

Ramp D Flyover

US27 TO SR-826 SB

SR826 SB FROM US27

SR 934 WB (870989)

SR 934 EB (870988)

WB SR-836 On Ramp

I-75 SB Ramp

MIA Off Ramp 4

I-395 EB

COMP SR-817

GRANADA BLVD

I-95 NB (870094)

I-95 SB (870093)

SR821 HEFT SB 21.4

SR821 SB HEFT 22.4

SR821 HEFT SB 34.0

SR 874 SB

NW 154 ST - W.B.

NW 154 ST - E.B.

SR821 RAMP SB 27.2

SR 90

SR 856

Port Boulevard

MIC Off Ramp

SW 424th Street

SR 932 (NW 103 St)

Ponce de Leon Blvd

SR821 SB HEFT 11.7

SR821 SB HEFT 23.5

SR948 EB

SR821 NB HEFT 6.04

SR821 NB HEFT 3.1

SR821 NB HEFT 11.7

SR821 NB HEFT 22.4

COMP SR-826

SR91 NB TPK 2.22

I-75 Rmp (SB) 39.2

I-75 Exp NB 39.2

SR-826 SB

SR874 E-N Ramp

WB SR-836 On Ramp

NW 42nd Court

SW 137th Ave. (NB)

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