US Bridges

STC3742;WAMSTAD RD over Boise River

Fair

Canyon County, Idaho · 1.2 S. 0.3 W. Parma · Structure no. 000000000027435

Built
1975
50 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
198 ft
2 main spans
Daily traffic
2,700
2023 count
Owner
Local
Other Local Agency

About this bridge

STC3742;WAMSTAD RD over Boise River is a prestressed concrete stringer/multi-beam or girder carrying STC3742;WAMSTAD RD over Boise River in Canyon County, Idaho. It was built in 1975, so it is 50 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 2,700 vehicles a day, roughly 16% of them trucks, projected to reach 4,050 by 2042. The structure is 198 ft (60.4 m) long and 38 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSTC3742;WAMSTAD RD
CrossesBoise River
Location1.2 S. 0.3 W. Parma
RouteCounty Highway 3742
CountyCanyon County
StateIdaho
Coordinates43.77019, -116.95197
Functional classRural Major 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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating64 US tons
Inventory rating31 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length198 ft (60.4 m)
Longest span97 ft (29.6 m)
Deck width38 ft (11.5 m)
Roadway width35 ft (10.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,700 (2023)
Projected traffic4,050 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local 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 STC3742;WAMSTAD RD over Boise River built?

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

What condition is STC3742;WAMSTAD RD over Boise River 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 September 2023.

How much traffic does STC3742;WAMSTAD RD over Boise River carry?

About 2,700 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is STC3742;WAMSTAD RD over Boise River?

The structure is 198 ft (60.4 m) long with a longest span of 97 ft (29.6 m) and a deck 38 ft wide.

Who owns STC3742;WAMSTAD RD over Boise River?

It is owned by the Other Local Agency.