US Bridges

Dillon Road over Rock Creek

Good

Boulder County, Colorado · 0.3 MI W of HWY 287 · Structure no. BC-68-4.7-RO

Built
2019
6 years old
Condition
Good
inspected February 2025
Type
Culvert
Concrete
Length
38 ft
3 main spans
Daily traffic
451
2023 count
Owner
County
County Highway Agency

About this bridge

Dillon Road over Rock Creek is a concrete culvert carrying Dillon Road over Rock Creek in Boulder County, Colorado. It was built in 2019, so it is 6 years old, younger than the Colorado average of 42.2 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 451 vehicles a day, roughly 19% of them trucks, projected to reach 541 by 2042. The structure is 38 ft (11.6 m) long and 35 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesDillon Road
CrossesRock Creek
Location0.3 MI W of HWY 287
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates39.95786, -105.08537
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert7 GoodSome minor problems.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.2 US tons
Inventory rating52.5 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans3
Design loadHL 93
Structure length38 ft (11.6 m)
Longest span12 ft (3.7 m)
Deck width35 ft (10.8 m)
Roadway width33 ft (10.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic451 (2023)
Projected traffic541 by 2042
Trucks19%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Dillon Road over Rock Creek built?

It was built in 2019, making it 6 years old in 2025.

What condition is Dillon Road over Rock Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2025.

How much traffic does Dillon Road over Rock Creek carry?

About 451 vehicles per day (2023 count), of which roughly 19% are trucks.

How long is Dillon Road over Rock Creek?

The structure is 38 ft (11.6 m) long with a longest span of 12 ft (3.7 m) and a deck 35 ft wide.

Who owns Dillon Road over Rock Creek?

It is owned by the County Highway Agency.