US Bridges

County Road over Cub River;s.Mapleton Br

Fair

Franklin County, Idaho · 1.7 S. 6.1 E. Preston · Structure no. 000000000023320

Built
1979
46 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
27 ft
1 main span
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

County Road over Cub River;s.Mapleton Br is a steel stringer/multi-beam or girder carrying County Road over Cub River;s.Mapleton Br in Franklin County, Idaho. It was built in 1979, so it is 46 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 50 vehicles a day, roughly 10% of them trucks, projected to reach 75 by 2039. The structure is 27 ft (8.2 m) long and 20 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesCounty Road
CrossesCub River;s.Mapleton Br
Location1.7 S. 6.1 E. Preston
RouteCounty Highway 0
CountyFranklin County
StateIdaho
Coordinates42.07308, -111.75856
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 protection7 GoodSome minor problems.
Last inspectionOctober 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating89 US tons
Inventory rating53 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length27 ft (8.2 m)
Longest span26 ft (7.9 m)
Deck width20 ft (6.1 m)
Roadway width19 ft (5.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic75 by 2039
Trucks10%
Lanes on structure2
Traffic directionTwo-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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road over Cub River;s.Mapleton Br built?

It was built in 1979, making it 46 years old in 2025.

What condition is County Road over Cub River;s.Mapleton Br 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 County Road over Cub River;s.Mapleton Br carry?

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

How long is County Road over Cub River;s.Mapleton Br?

The structure is 27 ft (8.2 m) long with a longest span of 26 ft (7.9 m) and a deck 20 ft wide.

Who owns County Road over Cub River;s.Mapleton Br?

It is owned by the County Highway Agency.