US Bridges

Mabey Lane over Lemhi River

FairPosted for load

Lemhi County, Idaho · 1.0 S. 0.1 E. Tendoy · Structure no. 000000000032670

Built
1968
57 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
44 ft
1 main span
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

Mabey Lane over Lemhi River is a wood or timber stringer/multi-beam or girder carrying Mabey Lane over Lemhi River in Lemhi County, Idaho. It was built in 1968, so it is 57 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. Its operating status is: posted for load restriction.

It carries about 50 vehicles a day, roughly 10% of them trucks, projected to reach 75 by 2039. The structure is 44 ft (13.4 m) long and 16 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesMabey Lane
CrossesLemhi River
Location1.0 S. 0.1 E. Tendoy
RouteCounty Highway 0
CountyLemhi County
StateIdaho
Coordinates44.94553, -113.64111
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating22 US tons
Inventory rating13 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length44 ft (13.4 m)
Longest span42 ft (12.8 m)
Deck width16 ft (4.9 m)
Roadway width15 ft (4.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic75 by 2039
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$416,000 (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Mabey Lane over Lemhi River built?

It was built in 1968, making it 57 years old in 2025.

What condition is Mabey Lane over Lemhi 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 April 2023.

How much traffic does Mabey Lane over Lemhi River carry?

About 50 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Mabey Lane over Lemhi River?

The structure is 44 ft (13.4 m) long with a longest span of 42 ft (12.8 m) and a deck 16 ft wide.

Who owns Mabey Lane over Lemhi River?

It is owned by the County Highway Agency.