Structure F-16-DD · Jefferson County, CO

SH 121 Ml over Ped Underpass Draw

Carries SH 121 Ml over Ped Underpass Draw, 0.2 Mi No Of Jct SH 470.

Overall conditionFair

Set by its lowest-rated component: Culvert at 6 of 9.

How ratings work
Culvertsets the rating6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
22 FT ACROSS25 FT0ELEVATION · LENGTHS TO SCALE
Culvert 6/9

A culvert 22 ft across with 2 openings. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights, so those are drawn as typical for a culvert.

Built1964rebuilt 1971
Length22.0 ft6.7 m
Daily traffic20,000counted 2020
Last inspectedJanuary 2025every 24 months

Location

StateColorado
CountyJefferson
Location0.2 Mi No Of Jct SH 470
CarriesSH 121 Ml
CrossesPed Underpass Draw
Coordinates39.55870, -105.08254

Physical Characteristics

MaterialConcrete
DesignCulvert
Total Length22.0 ft (6.7 m)
Max Span9.8 ft (3 m)
Deck Width169.3 ft (51.6 m)
Deck Area345.7 sq m
Main Spans2
Year Built1964 (reconstructed 1971)

Traffic

Avg Daily Traffic20,000 (2020)
Truck Traffic1%
Lanes On Bridge4

Inspection & Ownership

Last InspectionJanuary 2025
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberF-16-DD

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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