US Bridges

N 41st ST (cr 59) over Left Hand Creek

Fair

Boulder County, Colorado · 325 Ft S of CO RD 26 · Structure no. BC-59-2.4-LT

Built
1960
65 years old
Condition
Fair
inspected February 2025
Type
Slab
Prestressed Concrete
Length
32 ft
1 main span
Daily traffic
226
2022 count
Owner
County
County Highway Agency

About this bridge

N 41st ST (cr 59) over Left Hand Creek is a prestressed concrete slab carrying N 41st ST (cr 59) over Left Hand Creek in Boulder County, Colorado. It was built in 1960, so it is 65 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 5 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 226 vehicles a day, roughly 25% of them trucks, projected to reach 271 by 2042. The structure is 32 ft (9.9 m) long and 27 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesN 41st ST (cr 59)
CrossesLeft Hand Creek
Location325 Ft S of CO RD 26
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.11513, -105.25884
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being 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 typeSlab
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length32 ft (9.9 m)
Longest span30 ft (9.2 m)
Deck width27 ft (8.3 m)
Roadway width27 ft (8.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic226 (2022)
Projected traffic271 by 2042
Trucks25%
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 N 41st ST (cr 59) over Left Hand Creek built?

It was built in 1960, making it 65 years old in 2025.

What condition is N 41st ST (cr 59) over Left Hand 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 N 41st ST (cr 59) over Left Hand Creek carry?

About 226 vehicles per day (2022 count), of which roughly 25% are trucks.

How long is N 41st ST (cr 59) over Left Hand Creek?

The structure is 32 ft (9.9 m) long with a longest span of 30 ft (9.2 m) and a deck 27 ft wide.

Who owns N 41st ST (cr 59) over Left Hand Creek?

It is owned by the County Highway Agency.