US Bridges

3rd Avenue over Oligarchy Ditch

Fair

Boulder County, Colorado · At Pace Street · Structure no. LONG-3RD-PACEST

Built
1969
56 years old, rebuilt 1974
Condition
Fair
inspected January 2025
Type
Culvert
Concrete
Length
48 ft
2 main spans
Daily traffic
16,797
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

3rd Avenue over Oligarchy Ditch is a concrete culvert carrying 3rd Avenue over Oligarchy Ditch in Boulder County, Colorado. It was built in 1969 and reconstructed in 1974, so it is 56 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 16,797 vehicles a day, roughly 13% of them trucks, projected to reach 20,157 by 2043. The structure is 48 ft (14.7 m) long and 352 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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Carries3rd Avenue
CrossesOligarchy Ditch
LocationAt Pace Street
RouteCity Street 0
CountyBoulder County
StateColorado
Coordinates40.16278, -105.07416
Functional classUrban Minor 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 inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating40 US tons
Inventory rating36 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length48 ft (14.7 m)
Longest span28 ft (8.4 m)
Deck width352 ft (107.3 m)
Roadway width187 ft (56.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,797 (2023)
Projected traffic20,157 by 2043
Trucks13%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 3rd Avenue over Oligarchy Ditch built?

It was built in 1969, making it 56 years old in 2025. It was reconstructed in 1974.

What condition is 3rd Avenue over Oligarchy Ditch 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 January 2025.

How much traffic does 3rd Avenue over Oligarchy Ditch carry?

About 16,797 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is 3rd Avenue over Oligarchy Ditch?

The structure is 48 ft (14.7 m) long with a longest span of 28 ft (8.4 m) and a deck 352 ft wide.

Who owns 3rd Avenue over Oligarchy Ditch?

It is owned by the City or Municipal Highway Agency.