US Bridges

N4720 over Ben Knight Trib. Creek

FairPosted for load

Adair County, Oklahoma · 1W 2S of US 59 · Structure no. 055570000000000

Built
1938
87 years old
Condition
Fair
inspected June 2024
Type
Slab
Concrete Continuous
Length
26 ft
2 main spans
Daily traffic
75
2022 count
Owner
County
County Highway Agency

About this bridge

N4720 over Ben Knight Trib. Creek is a concrete continuous slab carrying N4720 over Ben Knight Trib. Creek in Adair County, Oklahoma. It was built in 1938, so it is 87 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 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 75 vehicles a day, roughly 10% of them trucks, projected to reach 120 by 2042. The structure is 26 ft (7.8 m) long and 26 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesN4720
CrossesBen Knight Trib. Creek
Location1W 2S of US 59
RouteCounty Highway N4720
CountyAdair County
StateOklahoma
Coordinates35.98473, -94.60159
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating27.7 US tons
Inventory rating16.6 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHL 93
Structure length26 ft (7.8 m)
Longest span10 ft (3 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic75 (2022)
Projected traffic120 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 statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$236,000
NavigationNo navigation control on waterway

Frequently asked questions

When was N4720 over Ben Knight Trib. Creek built?

It was built in 1938, making it 87 years old in 2025.

What condition is N4720 over Ben Knight Trib. 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 June 2024.

How much traffic does N4720 over Ben Knight Trib. Creek carry?

About 75 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is N4720 over Ben Knight Trib. Creek?

The structure is 26 ft (7.8 m) long with a longest span of 10 ft (3 m) and a deck 26 ft wide.

Who owns N4720 over Ben Knight Trib. Creek?

It is owned by the County Highway Agency.