US Bridges

County Road 129 over Little Snake River

Fair

Routt County, Colorado · 48.6 MI N of US HWY 40 · Structure no. 107012961.60941

Built
1975
50 years old
Condition
Fair
inspected October 2024
Type
Girder and Floorbeam System
Steel
Length
100 ft
2 main spans
Daily traffic
85
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 129 over Little Snake River is a steel girder and floorbeam system carrying County Road 129 over Little Snake River in Routt County, Colorado. It was built in 1975, so it is 50 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 85 vehicles a day, roughly 54% of them trucks, projected to reach 101 by 2042. The structure is 100 ft (30.6 m) long and 24 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesCounty Road 129
CrossesLittle Snake River
Location48.6 MI N of US HWY 40
RouteCounty Highway 0
CountyRoutt County
StateColorado
Coordinates40.9964, -107.15065
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating25.2 US tons
Inventory rating15.1 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckCorrugated steel
Main spans2
Design loadHS 20
Structure length100 ft (30.6 m)
Longest span50 ft (15.1 m)
Deck width24 ft (7.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic85 (2023)
Projected traffic101 by 2042
Trucks54%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 County Road 129 over Little Snake River built?

It was built in 1975, making it 50 years old in 2025.

What condition is County Road 129 over Little Snake River 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 October 2024.

How much traffic does County Road 129 over Little Snake River carry?

About 85 vehicles per day (2023 count), of which roughly 54% are trucks.

How long is County Road 129 over Little Snake River?

The structure is 100 ft (30.6 m) long with a longest span of 50 ft (15.1 m) and a deck 24 ft wide.

Who owns County Road 129 over Little Snake River?

It is owned by the County Highway Agency.