US Bridges

CO RD 54A over Middle Boulder Creek

FairPosted for load

Boulder County, Colorado · Castle Rock Pull Off · Structure no. BCPOS-UPPER BR

Built
1917
108 years old
Condition
Fair
inspected January 2025
Type
Girder and Floorbeam System
Steel
Length
33 ft
1 main span
Daily traffic
66
2023 count
Owner
Local
Other Local Agency

About this bridge

CO RD 54A over Middle Boulder Creek is a steel girder and floorbeam system carrying CO RD 54A over Middle Boulder Creek in Boulder County, Colorado. It was built in 1917, so it is 108 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. Its operating status is: posted for load restriction.

It carries about 66 vehicles a day, roughly 2% of them trucks, projected to reach 79 by 2043. The structure is 33 ft (10.1 m) long and 17 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesCO RD 54A
CrossesMiddle Boulder Creek
LocationCastle Rock Pull Off
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates39.97916, -105.45441
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry7: Better than present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating12.2 US tons
Inventory rating7.3 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length33 ft (10.1 m)
Longest span29 ft (8.7 m)
Deck width17 ft (5.1 m)
Roadway width15 ft (4.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic66 (2023)
Projected traffic79 by 2043
Trucks2%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$897,000 (2019 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was CO RD 54A over Middle Boulder Creek built?

It was built in 1917, making it 108 years old in 2025.

What condition is CO RD 54A over Middle 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 CO RD 54A over Middle Boulder Creek carry?

About 66 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is CO RD 54A over Middle Boulder Creek?

The structure is 33 ft (10.1 m) long with a longest span of 29 ft (8.7 m) and a deck 17 ft wide.

Who owns CO RD 54A over Middle Boulder Creek?

It is owned by the Other Local Agency.