US Bridges

Lookout Road over Boulder Cr. Supply Ditch

Good

Boulder County, Colorado · 0.28 MI E of Spine Road · Structure no. BOLD-17-0.28-1A

Built
1996
29 years old
Condition
Good
inspected January 2025
Type
Culvert
Concrete
Length
20 ft
1 main span
Daily traffic
10,395
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Lookout Road over Boulder Cr. Supply Ditch is a concrete culvert carrying Lookout Road over Boulder Cr. Supply Ditch in Boulder County, Colorado. It was built in 1996, so it is 29 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 10,395 vehicles a day, roughly 4% of them trucks, projected to reach 12,474 by 2043. The structure is 20 ft (6.2 m) long and 60 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesLookout Road
CrossesBoulder Cr. Supply Ditch
Location0.28 MI E of Spine Road
RouteCity Street 0
CountyBoulder County
StateColorado
Coordinates40.0727, -105.19708
Functional classUrban Minor Arterial

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 inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadHS 20
Structure length20 ft (6.2 m)
Longest span20 ft (6.2 m)
Deck width60 ft (18.3 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,395 (2023)
Projected traffic12,474 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Lookout Road over Boulder Cr. Supply Ditch built?

It was built in 1996, making it 29 years old in 2025.

What condition is Lookout Road over Boulder Cr. Supply Ditch 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 January 2025.

How much traffic does Lookout Road over Boulder Cr. Supply Ditch carry?

About 10,395 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Lookout Road over Boulder Cr. Supply Ditch?

The structure is 20 ft (6.2 m) long with a longest span of 20 ft (6.2 m) and a deck 60 ft wide.

Who owns Lookout Road over Boulder Cr. Supply Ditch?

It is owned by the City or Municipal Highway Agency.