US Bridges

Long Gulch Road over M.Fk.Boise River

FairPosted for load

Boise County, Idaho · 10.0 N. 8.5 W. Prairie · Structure no. 000000000027903

Built
1954
71 years old, rebuilt 1995
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
185 ft
3 main spans
Daily traffic
130
2023 count
Owner
Local
Other Local Agency

About this bridge

Long Gulch Road over M.Fk.Boise River is a steel continuous stringer/multi-beam or girder carrying Long Gulch Road over M.Fk.Boise River in Boise County, Idaho. It was built in 1954 and reconstructed in 1995, so it is 71 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. Its operating status is: posted for load restriction.

It carries about 130 vehicles a day, roughly 8% of them trucks, projected to reach 195 by 2042. The structure is 185 ft (56.4 m) long and 14 ft wide. If it were closed, the detour would be 67.7 mi (109 km).

Location

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CarriesLong Gulch Road
CrossesM.Fk.Boise River
Location10.0 N. 8.5 W. Prairie
RouteCounty Highway 0
CountyBoise County
StateIdaho
Coordinates43.65004, -115.74417
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
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
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating19 US tons
Inventory rating14 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckWood or timber
Main spans3
Design loadH 20
Structure length185 ft (56.4 m)
Longest span69 ft (21 m)
Deck width14 ft (4.3 m)
Roadway width13 ft (3.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic130 (2023)
Projected traffic195 by 2042
Trucks8%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed67.7 mi (109 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$1.5 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Long Gulch Road over M.Fk.Boise River built?

It was built in 1954, making it 71 years old in 2025. It was reconstructed in 1995.

What condition is Long Gulch Road over M.Fk.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 2024.

How much traffic does Long Gulch Road over M.Fk.Boise River carry?

About 130 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is Long Gulch Road over M.Fk.Boise River?

The structure is 185 ft (56.4 m) long with a longest span of 69 ft (21 m) and a deck 14 ft wide.

Who owns Long Gulch Road over M.Fk.Boise River?

It is owned by the Other Local Agency.