US Bridges

Jackknife Road over Jackknife Creek

FairPosted for load

Bonneville County, Idaho · 0.9 N. 14.8 E. Grays Lake · Structure no. 000000000031020

Built
1970
55 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
26 ft
1 main span
Daily traffic
150
2023 count
Owner
County
County Highway Agency

About this bridge

Jackknife Road over Jackknife Creek is a wood or timber stringer/multi-beam or girder carrying Jackknife Road over Jackknife Creek in Bonneville County, Idaho. It was built in 1970, so it is 55 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 150 vehicles a day, roughly 20% of them trucks, projected to reach 225 by 2039. The structure is 26 ft (7.9 m) long and 16 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesJackknife Road
CrossesJackknife Creek
Location0.9 N. 14.8 E. Grays Lake
RouteCounty Highway 0
CountyBonneville County
StateIdaho
Coordinates43.04414, -111.08678
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating8 US tons
Inventory rating0 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadH 15
Structure length26 ft (7.9 m)
Longest span25 ft (7.6 m)
Deck width16 ft (4.9 m)
Roadway width15 ft (4.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic150 (2023)
Projected traffic225 by 2039
Trucks20%
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$319,000 (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Jackknife Road over Jackknife Creek built?

It was built in 1970, making it 55 years old in 2025.

What condition is Jackknife Road over Jackknife Creek 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 Jackknife Road over Jackknife Creek carry?

About 150 vehicles per day (2023 count), of which roughly 20% are trucks.

How long is Jackknife Road over Jackknife Creek?

The structure is 26 ft (7.9 m) long with a longest span of 25 ft (7.6 m) and a deck 16 ft wide.

Who owns Jackknife Road over Jackknife Creek?

It is owned by the County Highway Agency.