US Bridges

Houston Road over Big Lost River

Fair

Custer County, Idaho · 1.5 S. 1.5 E. Mackay · Structure no. 000000000031695

Built
1973
52 years old
Condition
Fair
inspected July 2023
Type
Tee Beam
Prestressed Concrete
Length
59 ft
1 main span
Daily traffic
170
2023 count
Owner
Local
Other Local Agency

About this bridge

Houston Road over Big Lost River is a prestressed concrete tee beam carrying Houston Road over Big Lost River in Custer County, Idaho. It was built in 1973, so it is 52 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 170 vehicles a day, roughly 13% of them trucks, projected to reach 255 by 2042. The structure is 59 ft (18 m) long and 26 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesHouston Road
CrossesBig Lost River
Location1.5 S. 1.5 E. Mackay
RouteCounty Highway 0
CountyCuster County
StateIdaho
Coordinates43.88689, -113.57878
Functional classRural Minor Collector

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating30 US tons
Inventory rating18 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length59 ft (18 m)
Longest span57 ft (17.4 m)
Deck width26 ft (8 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic170 (2023)
Projected traffic255 by 2042
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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$617,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Houston Road over Big Lost River built?

It was built in 1973, making it 52 years old in 2025.

What condition is Houston Road over Big Lost 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 July 2023.

How much traffic does Houston Road over Big Lost River carry?

About 170 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is Houston Road over Big Lost River?

The structure is 59 ft (18 m) long with a longest span of 57 ft (17.4 m) and a deck 26 ft wide.

Who owns Houston Road over Big Lost River?

It is owned by the Other Local Agency.