US Bridges

1st Street North over Phyllis Canal

Fair

Canyon County, Idaho · In NAMPA;1st Street North · Structure no. 000000000027705

Built
1978
47 years old, rebuilt 1981
Condition
Fair
inspected February 2023
Type
Tee Beam
Prestressed Concrete
Length
27 ft
1 main span
Daily traffic
2,300
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

1st Street North over Phyllis Canal is a prestressed concrete tee beam carrying 1st Street North over Phyllis Canal in Canyon County, Idaho. It was built in 1978 and reconstructed in 1981, so it is 47 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 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 2,300 vehicles a day, roughly 10% of them trucks, projected to reach 3,450 by 2042. The structure is 27 ft (8.2 m) long and 51 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Carries1st Street North
CrossesPhyllis Canal
LocationIn NAMPA;1st Street North
RouteCity Street 0
StateIdaho
Coordinates43.58367, -116.56189
Functional classUrban Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2023
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 geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.6 US tons
Inventory rating21.8 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length27 ft (8.2 m)
Longest span26 ft (7.9 m)
Deck width51 ft (15.6 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,300 (2023)
Projected traffic3,450 by 2042
Trucks10%
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

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$675,000 (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 1st Street North over Phyllis Canal built?

It was built in 1978, making it 47 years old in 2025. It was reconstructed in 1981.

What condition is 1st Street North 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 February 2023.

How much traffic does 1st Street North over Phyllis Canal carry?

About 2,300 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is 1st Street North over Phyllis Canal?

The structure is 27 ft (8.2 m) long with a longest span of 26 ft (7.9 m) and a deck 51 ft wide.

Who owns 1st Street North over Phyllis Canal?

It is owned by the City or Municipal Highway Agency.