US Bridges

County Road 129 over Mad Creek

Fair

Routt County, Colorado · 5.4 MI N of US HWY 40 · Structure no. 107012905.40912

Built
1981
44 years old
Condition
Fair
inspected October 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
85 ft
1 main span
Daily traffic
2,762
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 129 over Mad Creek is a prestressed concrete box beam or girders - multiple carrying County Road 129 over Mad Creek in Routt County, Colorado. It was built in 1981, so it is 44 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 2,762 vehicles a day, roughly 35% of them trucks, projected to reach 3,287 by 2042. The structure is 85 ft (25.9 m) long and 28 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesCounty Road 129
CrossesMad Creek
Location5.4 MI N of US HWY 40
RouteCounty Highway 0
CountyRoutt County
StateColorado
Coordinates40.5655, -106.88912
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
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 evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating69.2 US tons
Inventory rating41.4 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadUnknown
Structure length85 ft (25.9 m)
Longest span79 ft (24.1 m)
Deck width28 ft (8.6 m)
Roadway width27 ft (8.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,762 (2023)
Projected traffic3,287 by 2042
Trucks35%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$466,000 (2018 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was County Road 129 over Mad Creek built?

It was built in 1981, making it 44 years old in 2025.

What condition is County Road 129 over Mad 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 October 2024.

How much traffic does County Road 129 over Mad Creek carry?

About 2,762 vehicles per day (2023 count), of which roughly 35% are trucks.

How long is County Road 129 over Mad Creek?

The structure is 85 ft (25.9 m) long with a longest span of 79 ft (24.1 m) and a deck 28 ft wide.

Who owns County Road 129 over Mad Creek?

It is owned by the County Highway Agency.