US Bridges

County Road 1 over Big Dry Creek

Fair

Boulder County, Colorado · 0.3 MI N of CO RD 20.5 · Structure no. WEL001.0-020.5A

Built
1995
30 years old
Condition
Fair
inspected February 2025
Type
Slab
Prestressed Concrete
Length
31 ft
1 main span
Daily traffic
9,859
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 1 over Big Dry Creek is a prestressed concrete slab carrying County Road 1 over Big Dry Creek in Boulder County, Colorado. It was built in 1995, so it is 30 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 9,859 vehicles a day, roughly 12% of them trucks, projected to reach 11,831 by 2043. The structure is 31 ft (9.4 m) long and 36 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesCounty Road 1
CrossesBig Dry Creek
Location0.3 MI N of CO RD 20.5
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.14487, -105.05531
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 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 rating58.2 US tons
Inventory rating36.3 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length31 ft (9.4 m)
Longest span29 ft (8.7 m)
Deck width36 ft (11 m)
Roadway width33 ft (10 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,859 (2023)
Projected traffic11,831 by 2043
Trucks12%
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 County Road 1 over Big Dry Creek built?

It was built in 1995, making it 30 years old in 2025.

What condition is County Road 1 over Big 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 County Road 1 over Big Dry Creek carry?

About 9,859 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is County Road 1 over Big Dry Creek?

The structure is 31 ft (9.4 m) long with a longest span of 29 ft (8.7 m) and a deck 36 ft wide.

Who owns County Road 1 over Big Dry Creek?

It is owned by the County Highway Agency.