US Bridges

County Road 103 over Middle St. Vrain Creek

Fair

Boulder County, Colorado · 0.5 Mile South West of ST · Structure no. BC-103-0.5-MSV1

Built
1993
32 years old
Condition
Fair
inspected January 2025
Type
Slab
Prestressed Concrete
Length
43 ft
1 main span
Daily traffic
170
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 103 over Middle St. Vrain Creek is a prestressed concrete slab carrying County Road 103 over Middle St. Vrain Creek in Boulder County, Colorado. It was built in 1993, so it is 32 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 170 vehicles a day, roughly 11% of them trucks, projected to reach 204 by 2043. The structure is 43 ft (13.1 m) long and 34 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesCounty Road 103
CrossesMiddle St. Vrain Creek
Location0.5 Mile South West of ST
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.17551, -105.4374
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating68.6 US tons
Inventory rating42.8 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length43 ft (13.1 m)
Longest span39 ft (11.9 m)
Deck width34 ft (10.4 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic170 (2023)
Projected traffic204 by 2043
Trucks11%
Lanes on structure2
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

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 County Road 103 over Middle St. Vrain Creek built?

It was built in 1993, making it 32 years old in 2025.

What condition is County Road 103 over Middle St. Vrain 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 County Road 103 over Middle St. Vrain Creek carry?

About 170 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is County Road 103 over Middle St. Vrain Creek?

The structure is 43 ft (13.1 m) long with a longest span of 39 ft (11.9 m) and a deck 34 ft wide.

Who owns County Road 103 over Middle St. Vrain Creek?

It is owned by the County Highway Agency.