US Bridges

SH 121 Ml over Deer Creek

Fair

Jefferson County, Colorado · 2.0 MI S of JCT SH 470 · Structure no. F-16-HZ

Built
1968
57 years old
Condition
Fair
inspected August 2023
Type
Culvert
Concrete
Length
32 ft
3 main spans
Daily traffic
23,000
2020 count
Owner
State
State Highway Agency

About this bridge

SH 121 Ml over Deer Creek is a concrete culvert carrying SH 121 Ml over Deer Creek in Jefferson County, Colorado. It was built in 1968, so it is 57 years old, older than the Colorado average of 42.2 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 23,000 vehicles a day, roughly 2% of them trucks, projected to reach 27,370 by 2040. The structure is 32 ft (9.8 m) long and 383 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

CarriesSH 121 Ml
CrossesDeer Creek
Location2.0 MI S of JCT SH 470
RouteState Highway 121B
Coordinates39.54626, -105.08844
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99.9 US tons
Inventory rating99.9 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans3
Design loadHS 20
Structure length32 ft (9.8 m)
Longest span12 ft (3.7 m)
Deck width383 ft (116.8 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic23,000 (2020)
Projected traffic27,370 by 2040
Trucks2%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SH 121 Ml over Deer Creek built?

It was built in 1968, making it 57 years old in 2025.

What condition is SH 121 Ml over Deer Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in August 2023.

How much traffic does SH 121 Ml over Deer Creek carry?

About 23,000 vehicles per day (2020 count), of which roughly 2% are trucks.

How long is SH 121 Ml over Deer Creek?

The structure is 32 ft (9.8 m) long with a longest span of 12 ft (3.7 m) and a deck 383 ft wide.

Who owns SH 121 Ml over Deer Creek?

It is owned by the State Highway Agency.