US Bridges

Twin Lakes Road over Bldr and Whiterock Ditch

Fair

Boulder County, Colorado · 0.2 MI E of 63rd Street · Structure no. BC-O-OSO-8A

Built
1975
50 years old
Condition
Fair
inspected January 2025
Type
Culvert
Concrete
Length
21 ft
2 main spans
Daily traffic
1,018
2023 count
Owner
County
County Highway Agency

About this bridge

Twin Lakes Road over Bldr and Whiterock Ditch is a concrete culvert carrying Twin Lakes Road over Bldr and Whiterock Ditch in Boulder County, Colorado. It was built in 1975, so it is 50 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 1,018 vehicles a day, roughly 4% of them trucks, projected to reach 1,222 by 2043. The structure is 21 ft (6.3 m) long and 52 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesTwin Lakes Road
CrossesBldr and Whiterock Ditch
Location0.2 MI E of 63rd Street
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.05731, -105.20251
Functional classUrban 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
Channel and channel protection8 Very GoodNo problems noted.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
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 typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length21 ft (6.3 m)
Longest span10 ft (3 m)
Deck width52 ft (15.8 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,018 (2023)
Projected traffic1,222 by 2043
Trucks4%
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 Twin Lakes Road over Bldr and Whiterock Ditch built?

It was built in 1975, making it 50 years old in 2025.

What condition is Twin Lakes Road over Bldr and Whiterock Ditch 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 Twin Lakes Road over Bldr and Whiterock Ditch carry?

About 1,018 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Twin Lakes Road over Bldr and Whiterock Ditch?

The structure is 21 ft (6.3 m) long with a longest span of 10 ft (3 m) and a deck 52 ft wide.

Who owns Twin Lakes Road over Bldr and Whiterock Ditch?

It is owned by the County Highway Agency.