US Bridges

Summit Flat Road over Smith Creek

Fair

Boise County, Idaho · 0.5 E. Pioneerville · Structure no. 000000000026660

Built
1974
51 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
21 ft
1 main span
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

Summit Flat Road over Smith Creek is a wood or timber stringer/multi-beam or girder carrying Summit Flat Road over Smith Creek in Boise County, Idaho. It was built in 1974, so it is 51 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.

It carries about 50 vehicles a day, roughly 10% of them trucks, projected to reach 75 by 2039. The structure is 21 ft (6.4 m) long and 15 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSummit Flat Road
CrossesSmith Creek
Location0.5 E. Pioneerville
RouteCounty Highway 0
CountyBoise County
StateIdaho
Coordinates43.96778, -115.84143
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating61 US tons
Inventory rating43 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length21 ft (6.4 m)
Longest span20 ft (6.1 m)
Deck width15 ft (4.7 m)
Roadway width14 ft (4.3 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 closed1.2 mi (2 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$284,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Summit Flat Road over Smith Creek built?

It was built in 1974, making it 51 years old in 2025.

What condition is Summit Flat Road over Smith 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 2023.

How much traffic does Summit Flat Road over Smith Creek carry?

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

How long is Summit Flat Road over Smith Creek?

The structure is 21 ft (6.4 m) long with a longest span of 20 ft (6.1 m) and a deck 15 ft wide.

Who owns Summit Flat Road over Smith Creek?

It is owned by the County Highway Agency.