US Bridges

N. 75th ST (cr 25) over Boulder Creek

Fair

Boulder County, Colorado · 0.1 MI S of Jay Road · Structure no. BC-25-10.8-BO

Built
1978
47 years old
Condition
Fair
inspected January 2025
Type
Tee Beam
Prestressed Concrete
Length
112 ft
2 main spans
Daily traffic
8,907
2023 count
Owner
County
County Highway Agency

About this bridge

N. 75th ST (cr 25) over Boulder Creek is a prestressed concrete tee beam carrying N. 75th ST (cr 25) over Boulder Creek in Boulder County, Colorado. It was built in 1978, so it is 47 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 8,907 vehicles a day, roughly 10% of them trucks, projected to reach 10,689 by 2043. The structure is 112 ft (34.1 m) long and 40 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesN. 75th ST (cr 25)
CrossesBoulder Creek
Location0.1 MI S of Jay Road
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.05143, -105.17819
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 inspectionJanuary 2025
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating40 US tons
Inventory rating36 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length112 ft (34.1 m)
Longest span53 ft (16.2 m)
Deck width40 ft (12.1 m)
Roadway width37 ft (11.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,907 (2023)
Projected traffic10,689 by 2043
Trucks10%
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 N. 75th ST (cr 25) over Boulder Creek built?

It was built in 1978, making it 47 years old in 2025.

What condition is N. 75th ST (cr 25) over Boulder 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 January 2025.

How much traffic does N. 75th ST (cr 25) over Boulder Creek carry?

About 8,907 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is N. 75th ST (cr 25) over Boulder Creek?

The structure is 112 ft (34.1 m) long with a longest span of 53 ft (16.2 m) and a deck 40 ft wide.

Who owns N. 75th ST (cr 25) over Boulder Creek?

It is owned by the County Highway Agency.