Total bridges
464
Public highway bridges in Jefferson County
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.
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
- 1920s 1
1920–1929
1 bridges
- 1930s 11
1930–1939
11 bridges
- 1940s 12
1940–1949
12 bridges
- 1950s 26
1950–1959
26 bridges
- 1960s
1960–1969
59 bridges
- 1970s
1970–1979
80 bridges
- 1980s
1980–1989
93 bridges
- 1990s
1990–1999
78 bridges
- 2000s
2000–2009
56 bridges
- 2010s 37
2010–2019
37 bridges
- 2020s 11
2020–2029
11 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).
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.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Larimer County | 559 | 49% | 49% | 2% | 1987 |
| Adams County | 535 | 43.9% | 49.2% | 6.9% | 1990 |
| Jefferson County (this page) | 464 | 33.8% | 59.9% | 6.3% | 1984 |
| Denver County | 458 | 41.9% | 56.3% | 1.7% | 1991 |
| Arapahoe County | 391 | 26.1% | 66.8% | 7.2% | 1984 |
| Mesa County | 319 | 35.1% | 63.3% | 1.6% | 1981 |
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).
- Hamilton County, TN · 464 bridges
- Calcasieu County, LA · 463 bridges
- Darke County, OH · 463 bridges
- Anderson County, SC · 463 bridges
Similar average build year
Nearest mean year-built outside CO (1984 here).
- Hennepin County, MN · avg 1984 · 936 bridges
- Duval County, FL · avg 1984 · 831 bridges
- Bell County, TX · avg 1984 · 660 bridges
- Steuben County, NY · avg 1984 · 627 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (464)
I 70 ML EBND
PoorOver: SH 391 ML
WHEATRIDGE, Jefferson, CO
Built 1967 Load: 29.4 t ADT: 57,000
RAMP TO I 70 EBND
PoorOver: I 70 ML R
END OF SH 58 @ I 70, Jefferson, CO
Built 1968 Load: 29.4 t ADT: 17,000
COUNTY ROAD 67
PoorOver: SOUTH PLATTE RIVER
5 MI NORTH OF DECKERS, Jefferson, CO
Built 1990 Load: 29.8 t ADT: 725
MCINTYRE STREET
PoorOver: SH 58 ML
2.9 MI E OF JCT SH 93, Jefferson, CO
Built 1973 Load: 31.7 t ADT: 18,523
I 76 ML WBND
PoorOver: RAMP TO SH 121 ML
IN ARVADA, Jefferson, CO
Built 1982 Load: 32.5 t ADT: 38,000
WARD ROAD
PoorOver: RALSTON CREEK
JUST NORTH OF 70TH AVE, Jefferson, CO
Built 1969 Load: 32.7 t ADT: 15,435
SH 391 ML
PoorOver: CLEAR CREEK
KIPLING 0.65 MI S OF I70, Jefferson, CO
Built 1969 Load: 32.7 t ADT: 37,000
I 70 ML WBND
PoorOver: US 40 ML
WEST OF DENVER, Jefferson, CO
Built 1969 Load: 34.5 t ADT: 35,000
I 76 ML EBND
PoorOver: RAMP TO SH 121 ML
I70 I76 SH121 INTERCHAN, Jefferson, CO
Built 1982 Load: 43.0 t ADT: 38,000
I 76 ML EBND
PoorOver: MARSHALL STREET
.75 MI E. OF WADSWORTH, Jefferson, CO
Built 1980 Load: 44.3 t ADT: 38,000
I 76 ML WBND
PoorOver: CLEAR CREEK
1.1 M W OF JCT SH 95, Jefferson, CO
Built 1984 Load: 47.6 t ADT: 38,000
I 76 ML WBND
PoorOver: MARSHALL STREET
IN ARVADA, Jefferson, CO
Built 1980 Load: 52.8 t ADT: 38,000
YOUNGFIELD CT
PoorOver: LOCAL DRAINAGE
N OF ALAMEDA AT PARK SER., Jefferson, CO
Built 1975 Load: 99.9 t ADT: 1,460
KENTUCKY DR
PoorOver: WEIR GULCH
1/2 BLK W OF PIERCE ST, Jefferson, CO
Built 1970 Load: 99.9 t ADT: 5,467
Read our methodology - how this data is sourced, computed, and verified.
Related
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.