US Bridges

Niwot Road (cr 34) over Dry Creek

Fair

Boulder County, Colorado · 0.7 MI E of ST HWY 119 · Structure no. BC-34-0.7-DC

Built
1985
40 years old
Condition
Fair
inspected February 2025
Type
Culvert
Concrete
Length
29 ft
2 main spans
Daily traffic
5,021
2023 count
Owner
County
County Highway Agency

About this bridge

Niwot Road (cr 34) over Dry Creek is a concrete culvert carrying Niwot Road (cr 34) over Dry Creek in Boulder County, Colorado. It was built in 1985, so it is 40 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 5,021 vehicles a day, roughly 9% of them trucks, projected to reach 6,026 by 2043. The structure is 29 ft (8.8 m) long and 68 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesNiwot Road (cr 34)
CrossesDry Creek
Location0.7 MI E of ST HWY 119
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.10152, -105.16283
Functional classUrban 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
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 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 length29 ft (8.8 m)
Longest span14 ft (4.2 m)
Deck width68 ft (20.7 m)
Roadway width66 ft (20 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,021 (2023)
Projected traffic6,026 by 2043
Trucks9%
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Niwot Road (cr 34) over Dry Creek built?

It was built in 1985, making it 40 years old in 2025.

What condition is Niwot Road (cr 34) over Dry 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 February 2025.

How much traffic does Niwot Road (cr 34) over Dry Creek carry?

About 5,021 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is Niwot Road (cr 34) over Dry Creek?

The structure is 29 ft (8.8 m) long with a longest span of 14 ft (4.2 m) and a deck 68 ft wide.

Who owns Niwot Road (cr 34) over Dry Creek?

It is owned by the County Highway Agency.