County profile · official public datasets

Durham County, NC

314 public highway bridges tracked in the FHWA National Bridge Inventory: 35.7% rated Good, 60.8% Fair, 3.5% Poor.

314
Public bridges: 35.7%
Good condition: 3.5%
Poor condition

The verdict

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

Durham County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 36%
lowest Poor share in state: 3.5%
Poor-condition share: 314
public highway bridges: 1984
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.

Durham County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Durham County ranks #36 of 100 North Carolina counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.5%). Durham County, North Carolina contains 314 public highway bridges. Roughly 35.7% are rated “Good,” 60.8% “Fair,” and 3.5% “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

314

Public highway bridges in Durham County

Good condition

35.7%

112 of 314 rated 7-9

Fair condition

60.8%

191 of 314 rated 5-6

Poor condition

3.5%

11 of 314 rated 4 or below

In-state Poor-share rank

#36 of 100

Among North Carolina counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 314 NBI-tracked bridges by lowest applicable component rating.

Good

35.7% (112)

Fair

60.8% (191)

Poor

3.5% (11)

Durham County's Poor-condition bridges carry 155,900 vehicle crossings a day

That is 2.5% of the county's reported daily bridge traffic on 3.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 14,173 crossings a day against 17,308 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 314 of 314 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

35.4% of Durham County's bridges have passed the 50-year mark

111 of the 314 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 35.7% 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 32.7% of the county's Poor-condition bridge traffic

US15/US501NBL over SR1308, built 1956, carries 51,000 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 11-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 155,900 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

4
1930s

3
1940s

5
1950s

27
1960s

46
1970s

37
1980s

57
1990s

46
2000s

55
2010s

29
2020s

5

What this shows Construction peaked in the 1980s, when 57 of the county's bridges still in the inventory were built, which is 18.2% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1984) matches the North Carolina average (1986).

How Durham County compares with North Carolina's closest counties by inventory size

The 5 North Carolina counties nearest Durham County in number of bridges, with their condition splits. Its 3.5% Poor share is the 1st-lowest of these 6. Its average build year of 1984 against a peer-group mean of 1982 is in line with the group.

Showing the 5 closest of 99 North Carolina counties eligible for comparison.

Bridge inventory size and condition shares for Durham County and the 5 North Carolina counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Davidson County	340	42.9%	52.9%	4.1%	1988
Iredell County	335	35.2%	54.6%	10.1%	1981
Johnston County	318	42.1%	53.5%	4.4%	1989
Durham County (this page)	314	35.7%	60.8%	3.5%	1984
Surry County	308	28.9%	62%	9.1%	1979
Rutherford County	298	40.3%	47.3%	12.4%	1974

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 Durham 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 Durham County, both outside North Carolina so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NC (314 bridges here).

Jackson County, AL · 314 bridges
Cloud County, KS · 314 bridges
Douglas County, KS · 314 bridges
Franklin County, MA · 314 bridges

Similar average build year

Nearest mean year-built outside NC (1984 here).

Hennepin County, MN · avg 1984 · 936 bridges
Duval County, FL · avg 1984 · 831 bridges
El Paso County, CO · avg 1984 · 686 bridges
Bell County, TX · avg 1984 · 660 bridges

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

All 314 Good 112 Fair 191 Poor 11

All bridges (314)

Sort:

Durham County Bridge Snapshot

Condition distribution

Durham County's Poor-condition bridges carry 155,900 vehicle crossings a day

35.4% of Durham County's bridges have passed the 50-year mark

One structure carries 32.7% of the county's Poor-condition bridge traffic

How Durham County compares with North Carolina'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 (314)

NC157

SR1121

NC147S

WOODCROFT PKWAY.

SR1322

I85 & US15

SR1827

I85

M.L.K.JR. PKWY

WEST KNOX STREET

SR2028

NC147 NBL

SR1959

NC54W.

NC54E

US15/501 NBL

NC147S.

SR1121

NC157

US501 N.B.L.

US501S

NC147S.

NC147N

NC147W

SR2028

NC98

NC147 SBL

SR2163

NC147NBL

NC54

NC98

NC147N.

LASALLE ST.

US15 US501S

SR1308

NC147S

SR2220

I40 WBL

I40E

SR1628

NC157

SR1464

NC147N

I85S US70E RAMP

SR1616

SR1671

SR1669

SR1401

NC147 SBL

SR1805

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