US Bridges

N1720 over Creek

Fair

Harmon County, Oklahoma · 2. N 1.5 E of Hollis · Structure no. 035820000000000

Built
1937
88 years old
Condition
Fair
inspected February 2024
Type
Slab
Concrete
Length
41 ft
3 main spans
Daily traffic
70
2022 count
Owner
County
County Highway Agency

About this bridge

N1720 over Creek is a concrete slab carrying N1720 over Creek in Harmon County, Oklahoma. It was built in 1937, so it is 88 years old, older than the Oklahoma 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 70 vehicles a day, roughly 10% of them trucks, projected to reach 112 by 2042. The structure is 41 ft (12.5 m) long and 26 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesN1720
CrossesCreek
Location2. N 1.5 E of Hollis
RouteCounty Highway N1720
CountyHarmon County
StateOklahoma
Coordinates34.71065, -99.89448
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2024
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 geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating21.1 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadUnknown
Structure length41 ft (12.5 m)
Longest span11 ft (3.3 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic70 (2022)
Projected traffic112 by 2042
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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$285,000
NavigationNo navigation control on waterway

Frequently asked questions

When was N1720 over Creek built?

It was built in 1937, making it 88 years old in 2025.

What condition is N1720 over 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 February 2024.

How much traffic does N1720 over Creek carry?

About 70 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is N1720 over Creek?

The structure is 41 ft (12.5 m) long with a longest span of 11 ft (3.3 m) and a deck 26 ft wide.

Who owns N1720 over Creek?

It is owned by the County Highway Agency.