US Bridges

Cedar Road over M. Fk. St. Maries River

Fair

Shoshone County, Idaho · At Clarkia · Structure no. 000000000030740

Built
1974
51 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
60 ft
1 main span
Daily traffic
40
2023 count
Owner
Local
Other Local Agency

About this bridge

Cedar Road over M. Fk. St. Maries River is a steel stringer/multi-beam or girder carrying Cedar Road over M. Fk. St. Maries River in Shoshone County, Idaho. It was built in 1974, so it is 51 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 40 vehicles a day, roughly 10% of them trucks, projected to reach 60 by 2039. The structure is 60 ft (18.3 m) long and 25 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesCedar Road
CrossesM. Fk. St. Maries River
LocationAt Clarkia
RouteCounty Highway 0
CountyShoshone County
StateIdaho
Coordinates47.0139, -116.24809
Functional classRural 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating25.8 US tons
Inventory rating18.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckCorrugated steel
Main spans1
Design loadHS 20
Structure length60 ft (18.3 m)
Longest span59 ft (18 m)
Deck width25 ft (7.7 m)
Roadway width23 ft (7.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40 (2023)
Projected traffic60 by 2039
Trucks10%
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$582,000 (2020 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Cedar Road over M. Fk. St. Maries River built?

It was built in 1974, making it 51 years old in 2025.

What condition is Cedar Road over M. Fk. St. Maries 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 2024.

How much traffic does Cedar Road over M. Fk. St. Maries River carry?

About 40 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Cedar Road over M. Fk. St. Maries River?

The structure is 60 ft (18.3 m) long with a longest span of 59 ft (18 m) and a deck 25 ft wide.

Who owns Cedar Road over M. Fk. St. Maries River?

It is owned by the Other Local Agency.