County profile · official public datasets

Jefferson County, CO

464 public highway bridges tracked in the FHWA National Bridge Inventory: 33.8% rated Good, 59.9% Fair, 6.3% Poor.

464
Public bridges
33.8%
Good condition
6.3%
Poor condition

The verdict

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

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

40th
of 64 on Poor share
6.3%
Poor-condition share
464
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.

Jefferson County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Jefferson County ranks #40 of 64 Colorado counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.3%). Jefferson County, Colorado contains 464 public highway bridges. Roughly 33.8% are rated “Good,” 59.9% “Fair,” and 6.3% “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

464

Public highway bridges in Jefferson County

Good condition

33.8%

157 of 464 rated 7-9

Fair condition

59.9%

278 of 464 rated 5-6

Poor condition

6.3%

29 of 464 rated 4 or below

In-state Poor-share rank

#40 of 64

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

Condition distribution

Share of 464 NBI-tracked bridges by lowest applicable component rating.

Good
33.8% (157)
Fair
59.9% (278)
Poor
6.3% (29)

Jefferson County's Poor-condition bridges carry 853,450 vehicle crossings a day

That is 10.1% of the county's reported daily bridge traffic on 6.3% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 29,429 crossings a day against 16,847 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 464 of 464 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

33.2% of Jefferson County's bridges have passed the 50-year mark

154 of the 464 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 33.8% 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 11.8% of the county's Poor-condition bridge traffic

US 6 ML over SH 121 ML, built 1972, carries 101,000 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 29-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 853,450 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Jefferson County's bridges were built

464 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 93 of the county's bridges still in the inventory were built, which is 20% 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 Colorado average (1982).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How Jefferson County compares with Colorado's closest counties by inventory size

The 5 Colorado counties nearest Jefferson County in number of bridges, with their condition splits. Its 6.3% Poor share is the 4th-lowest of these 6. Its average build year of 1984 against a peer-group mean of 1987 is in line with the group.

Showing the 5 closest of 63 Colorado counties eligible for comparison.

Bridge inventory size and condition shares for Jefferson County and the 5 Colorado counties closest to it in inventory size
County Bridges Poor
Larimer County 559 2%
Adams County 535 6.9%
Jefferson County (this page) 464 6.3%
Denver County 458 1.7%
Arapahoe County 391 7.2%
Mesa County 319 1.6%

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

Similar inventory size

Nearest county inventories outside CO (464 bridges here).

Similar average build year

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

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

Fair-condition bridges (278)

PARK AVENUE

Fair

Over: BEAR CREEK

AT INTER. WITH SH 8, Jefferson, CO

Built 1926 Load: 6.5 t ADT: 220

92ND AVENUE

Fair

Over: US 36 ML

JUST W OF SHERIDAN BLVD, Jefferson, CO

Built 1983 Load: 7.0 t ADT: 23,806

JOYCE STREET

Fair

Over: RALSTON CREEK

0.06 MI NORTH OF 68TH AVE, Jefferson, CO

Built 1975 Load: 10.9 t ADT: 110

RMP TO EB I70/I76

Fair

Over: I 70 ML SH 121 R

IN ARVADA, Jefferson, CO

Built 1985 Load: 13.0 t ADT: 38,000

NFSR 543

Fair

Over: BUFFALO CREEK

4.4 MI FROM CR 126, Jefferson, CO

Built 1951 Load: 14.3 t ADT: 1

DUNRAVEN STREET

Fair

Over: VAN BIBBER CREEK

JUST NORTH OF 60TH PLACE, Jefferson, CO

Built 1972 Load: 14.8 t ADT: 160

SH 470 ML WBND

Fair

Over: I 70 ML

JCT. I70 & 470, Jefferson, CO

Built 1987 Load: 15.5 t ADT: 35,000

SH 72 ML

Fair

Over: FARMERS HIGHLINE CANAL

INDIANA ST ABOUT 7800 N, Jefferson, CO

Built 1954 Load: 16.2 t ADT: 16,000

SH 121 ML

Fair

Over: CLEAR CREEK

S. edge 70 76 ramp 121, Jefferson, CO

Built 1941 Load: 16.3 t ADT: 38,000

CANON STREET

Fair

Over: BEAR CREEK

AT INTER WITH SH 8, Jefferson, CO

Built 1945 Load: 16.3 t ADT: 102

US 40 ML

Fair

Over: I 70 ML

1.8 MI E OF JCT SH 74, Jefferson, CO

Built 1970 Load: 16.8 t ADT: 2,300

NOLAN STREET

Fair

Over: RALSTON CREEK

0.06 MI N OF 58TH AVENUE, Jefferson, CO

Built 1950 Load: 17.2 t ADT: 576

KIPLING PARKWAY AR

Fair

Over: MASSEY DRAW AR

.1 MI N.OF JCT470&KIPLING, Jefferson, CO

Built 1987 Load: 17.7 t ADT: 49,000

74TH AVENUE

Fair

Over: CROKE CANAL

.1 MI W OF CARR STREET, Jefferson, CO

Built 1955 Load: 17.9 t ADT: 3,181

MAIN STREET

Fair

Over: DRAINAGE

W. OF KIPLING STREET, Jefferson, CO

Built 1942 Load: 18.1 t ADT: 1,100

CARR STREET

Fair

Over: RALSTON CREEK

JUST SOUTH OF BROOKS DR, Jefferson, CO

Built 1980 Load: 19.0 t ADT: 6,962

SH 8 ML

Fair

Over: STRAINS GULCH

0.75 MI S OF MORRISON, Jefferson, CO

Built 1935 Load: 19.1 t ADT: 4,000

KIPLING PARKWAY

Fair

Over: VAN BIBBER CREEK

JUST SOUTH OF 58TH AVENUE, Jefferson, CO

Built 1987 Load: 19.9 t ADT: 19,868

I 70 ML WBND

Fair

Over: COUNTY RD. 93

MORRISON INTCHNG, Jefferson, CO

Built 1969 Load: 20.0 t ADT: 35,000

PIERCE ST

Fair

Over: WEIR GULCH

AT KENTUCKY AVENUE, Jefferson, CO

Built 1966 Load: 20.1 t ADT: 6,278

KIPLING STREET

Fair

Over: FARMERS HIGHLINE CANAL

0.1 MI NORTH OF 80TH AVE, Jefferson, CO

Built 1971 Load: 20.9 t ADT: 9,958

KIPLING STREET

Fair

Over: CROKE CANAL

0.15 MI NORTH OF 80TH AVE, Jefferson, CO

Built 1971 Load: 21.3 t ADT: 9,958

SH 72 ML

Fair

Over: VAN BIBBER CREEK

WARD RD ARVADA, Jefferson, CO

Built 1972 Load: 21.4 t ADT: 28,000

SH 74 ML

Fair

Over: KERR GULCH

0.8 MI E OF KITTREDGE, Jefferson, CO

Built 1956 Load: 21.5 t ADT: 3,300

COUNTY ROAD 122

Fair

Over: SOUTH TURKEY CREEK

3 MI S OF TINYTOWN, Jefferson, CO

Built 1991 Load: 21.7 t ADT: 1,020

44TH AVENUE

Fair

Over: CLEAR CREEK

.71 MI EAST OF KIPLING, Jefferson, CO

Built 1974 Load: 21.7 t ADT: 13,333

COUNTY ROAD 122

Fair

Over: TURKEY CREEK

JUST SOUTH OF US285, Jefferson, CO

Built 1948 Load: 22.2 t ADT: 1,204

US 6 ML

Fair

Over: ELK CREEK

4.3 MI E OF JCT SH 119, Jefferson, CO

Built 1950 Load: 22.2 t ADT: 7,500

COUNTY ROAD 67

Fair

Over: SOUTH PLATTE RIVER

.1 MI N OF DECKERS, Jefferson, CO

Built 1988 Load: 22.3 t ADT: 849

80TH AVENUE

Fair

Over: CROKE CANAL

.28 MI E OF KIPLING ST, Jefferson, CO

Built 1930 Load: 22.5 t ADT: 16,690

I 70 ML EBND

Fair

Over: COUNTY RD 93

Morrison-Red Rocks Int., Jefferson, CO

Built 1969 Load: 22.8 t ADT: 35,000

I 70 ML

Fair

Over: LENA GULCH

0.7 MI E OF W COLFAX, Jefferson, CO

Built 1968 Load: 23.0 t ADT: 87,000

KEN CARYL AVE

Fair

Over: MASSEY DRAW

.1 MI E OF GARRISON, Jefferson, CO

Built 1996 Load: 23.0 t ADT: 12,694

80TH AVENUE

Fair

Over: FARMERS HIGHLINE CANAL

.15 MI E OF KIPLING ST, Jefferson, CO

Built 1930 Load: 23.2 t ADT: 16,690

US 6 ML

Fair

Over: CLEAR CREEK

5.1 MI E OF JCT SH 119, Jefferson, CO

Built 1950 Load: 23.6 t ADT: 7,500

COUNTY ROAD 122

Fair

Over: SOUTH TURKEY CREEK

3.9 MI S OF TINYTOWN, Jefferson, CO

Built 1991 Load: 23.7 t ADT: 933

SH 74 ML

Fair

Over: I 70 ML

AT JCT I 70 EL RANCHO, Jefferson, CO

Built 1973 Load: 23.7 t ADT: 16,000

COUNTY ROAD 74

Fair

Over: UPPER BEAR CREEK

3 MI W JCT EVERGN LAKE, Jefferson, CO

Built 1992 Load: 24.3 t ADT: 1,308

FIELD STREET

Fair

Over: COON CREEK

0.5 MI S OF BELLEVIEW AVE, Jefferson, CO

Built 1975 Load: 24.3 t ADT: 2,054

CORWINA PARK RD

Fair

Over: BEAR CREEK

CORWINA PARK, Jefferson, CO

Built 1972 Load: 24.5 t ADT: 146

US 6 ML

Fair

Over: MCINTYRE GULCH

IN LAKEWOOD, Jefferson, CO

Built 1942 Load: 24.5 t ADT: 101,000

NB RAMP TO I70/I76

Fair

Over: CLEAR CREEK R

IN WHEATRIDGE, Jefferson, CO

Built 1980 Load: 24.6 t ADT: 59,000

COUNTY ROAD 67

Fair

Over: SOUTH PLATTE RIVER

INT OF CO RDS 67 & 97, Jefferson, CO

Built 1978 Load: 24.7 t ADT: 721

I 70 ML WBND

Fair

Over: CLEAR CREEK

WHEATRIDGE, Jefferson, CO

Built 1968 Load: 25.0 t ADT: 52,000

COUNTY ROAD 74

Fair

Over: UPPER BEAR CREEK

2.6 MI W JCT EVERGRN LAKE, Jefferson, CO

Built 1992 Load: 25.1 t ADT: 1,295

GARRISON STREET

Fair

Over: LAKEWOOD GULCH

JUST NORTH OF 9TH AVENUE, Jefferson, CO

Built 1940 Load: 25.2 t ADT: 9,987

48TH AVENUE

Fair

Over: CROKE CANAL

WEST OF INDIANA STREET, Jefferson, CO

Built 1984 Load: 25.3 t ADT: 370

SH 121 ML

Fair

Over: ARVADA CHANNEL

0.1 MI. N. OF I 76, Jefferson, CO

Built 1982 Load: 25.5 t ADT: 58,000

SH 470 ML EBND

Fair

Over: US 285 ML

2 MI S OF MORRISON, Jefferson, CO

Built 1988 Load: 25.5 t ADT: 33,000

PLAINVIEW ROAD

Fair

Over: COAL CREEK

0.25 MI N OF SH 72, Jefferson, CO

Built 1990 Load: 25.8 t ADT: 75
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.