US Bridges

Stc 3770;STAR RD over Phyllis Canal

Fair

Ada County, Idaho · 1.8 S. Star · Structure no. 000000000019745

Built
1967
58 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
43 ft
1 main span
Daily traffic
11,000
2023 count
Owner
County
County Highway Agency

About this bridge

Stc 3770;STAR RD over Phyllis Canal is a prestressed concrete stringer/multi-beam or girder carrying Stc 3770;STAR RD over Phyllis Canal in Ada County, Idaho. It was built in 1967, so it is 58 years old, older than the Idaho average of 45.3 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 11,000 vehicles a day, roughly 6% of them trucks, projected to reach 16,500 by 2042. The structure is 43 ft (13.1 m) long and 37 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesStc 3770;STAR RD
CrossesPhyllis Canal
Location1.8 S. Star
RouteCounty Highway 3770
CountyAda County
StateIdaho
Coordinates43.66648, -116.49336
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating35.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length43 ft (13.1 m)
Longest span42 ft (12.8 m)
Deck width37 ft (11.2 m)
Roadway width34 ft (10.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,000 (2023)
Projected traffic16,500 by 2042
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Stc 3770;STAR RD over Phyllis Canal built?

It was built in 1967, making it 58 years old in 2025.

What condition is Stc 3770;STAR RD over Phyllis Canal 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 October 2024.

How much traffic does Stc 3770;STAR RD over Phyllis Canal carry?

About 11,000 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is Stc 3770;STAR RD over Phyllis Canal?

The structure is 43 ft (13.1 m) long with a longest span of 42 ft (12.8 m) and a deck 37 ft wide.

Who owns Stc 3770;STAR RD over Phyllis Canal?

It is owned by the County Highway Agency.