US Bridges

County Road 4 over Little Thompson River

Fair

Larimer County, Colorado · 0.9 MI E of CO RD 21 · Structure no. LR4-0.9-21-A

Built
1984
41 years old
Condition
Fair
inspected May 2023
Type
Tee Beam
Prestressed Concrete
Length
75 ft
1 main span
Daily traffic
1,228
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 4 over Little Thompson River is a prestressed concrete tee beam carrying County Road 4 over Little Thompson River in Larimer County, Colorado. It was built in 1984, so it is 41 years old, younger 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 1,228 vehicles a day, roughly 18% of them trucks, projected to reach 1,535 by 2043. The structure is 75 ft (23 m) long and 39 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesCounty Road 4
CrossesLittle Thompson River
Location0.9 MI E of CO RD 21
RouteCounty Highway 0
CountyLarimer County
StateColorado
Coordinates40.27597, -105.11319
Functional classRural Minor 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 inspectionMay 2023
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 geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.4 US tons
Inventory rating33.6 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length75 ft (23 m)
Longest span70 ft (21.3 m)
Deck width39 ft (11.9 m)
Roadway width37 ft (11.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,228 (2023)
Projected traffic1,535 by 2043
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 4 over Little Thompson River built?

It was built in 1984, making it 41 years old in 2025.

What condition is County Road 4 over Little Thompson 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 May 2023.

How much traffic does County Road 4 over Little Thompson River carry?

About 1,228 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is County Road 4 over Little Thompson River?

The structure is 75 ft (23 m) long with a longest span of 70 ft (21.3 m) and a deck 39 ft wide.

Who owns County Road 4 over Little Thompson River?

It is owned by the County Highway Agency.