US Bridges

IRR BIA RTE N12 over Slick Rock Creek

Fair

Apache County, Arizona · South of Fort Defiance Az · Structure no. 00000000000N665

Built
1967
58 years old, rebuilt 1984
Condition
Fair
inspected April 2023
Type
Culvert
Concrete Continuous
Length
40 ft
3 main spans
Daily traffic
14,062
2023 count
Owner
Federal
Bureau of Indian Affairs

About this bridge

IRR BIA RTE N12 over Slick Rock Creek is a concrete continuous culvert carrying IRR BIA RTE N12 over Slick Rock Creek in Apache County, Arizona. It was built in 1967 and reconstructed in 1984, so it is 58 years old, older than the Arizona average of 47.8 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 14,062 vehicles a day, roughly 10% of them trucks, projected to reach 11,700 by 2040. The structure is 40 ft (12.1 m) long and 98 ft wide. If it were closed, the detour would be 9.3 mi (15 km).

Location

Open in Google Maps
CarriesIRR BIA RTE N12
CrossesSlick Rock Creek
LocationSouth of Fort Defiance Az
RouteFederal Lands Road 0N12
CountyApache County
StateArizona
Coordinates35.73203, -109.05797
Functional classUrban 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
Channel and channel protection2 CriticalAdvanced deterioration of primary structural elements. Bridge may be closed until corrective action is taken.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
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 adequacy2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating97.4 US tons
Inventory rating58.4 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadHS 20
Structure length40 ft (12.1 m)
Longest span12 ft (3.8 m)
Deck width98 ft (30 m)
Roadway width72 ft (22 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,062 (2023)
Projected traffic11,700 by 2040
Trucks10%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.3 mi (15 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerBureau of Indian Affairs
Maintained byBureau of Indian Affairs
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$375,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was IRR BIA RTE N12 over Slick Rock Creek built?

It was built in 1967, making it 58 years old in 2025. It was reconstructed in 1984.

What condition is IRR BIA RTE N12 over Slick Rock 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 April 2023.

How much traffic does IRR BIA RTE N12 over Slick Rock Creek carry?

About 14,062 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is IRR BIA RTE N12 over Slick Rock Creek?

The structure is 40 ft (12.1 m) long with a longest span of 12 ft (3.8 m) and a deck 98 ft wide.

Who owns IRR BIA RTE N12 over Slick Rock Creek?

It is owned by the Bureau of Indian Affairs.