US Bridges

Route 311 over Unknown Stream

Fair

Maui County, Hawaii · 4.69 S Mokulele HWY · Structure no. 009003110300469

Built
2005
20 years old
Condition
Fair
inspected February 2025
Type
Culvert
Concrete
Length
38 ft
3 main spans
Daily traffic
34,300
2017 count
Owner
State
State Highway Agency

About this bridge

Route 311 over Unknown Stream is a concrete culvert carrying Route 311 over Unknown Stream in Maui County, Hawaii. It was built in 2005, so it is 20 years old, younger than the Hawaii average of 63.8 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 34,300 vehicles a day, projected to reach 40,200 by 2027. The structure is 38 ft (11.7 m) long and 109 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesRoute 311
CrossesUnknown Stream
Location4.69 S Mokulele HWY
RouteU.S. Route 311
CountyMaui County
StateHawaii
Coordinates20.81004, -156.46829
Functional classRural Principal Arterial - Other

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 protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating95.7 US tons
Inventory rating74 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans3
Design loadHL 93
Structure length38 ft (11.7 m)
Longest span12 ft (3.7 m)
Deck width109 ft (33.2 m)
Roadway width107 ft (32.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic34,300 (2017)
Projected traffic40,200 by 2027
Trucks0%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Route 311 over Unknown Stream built?

It was built in 2005, making it 20 years old in 2025.

What condition is Route 311 over Unknown Stream 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 Route 311 over Unknown Stream carry?

About 34,300 vehicles per day (2017 count).

How long is Route 311 over Unknown Stream?

The structure is 38 ft (11.7 m) long with a longest span of 12 ft (3.7 m) and a deck 109 ft wide.

Who owns Route 311 over Unknown Stream?

It is owned by the State Highway Agency.