US Bridges

KY-18 over Allen Fork

Fair

Boone County, Kentucky · 1.2 MI West of JCT Ky 338 · Structure no. 008B00012N

Built
1958
67 years old
Condition
Fair
inspected June 2023
Type
Culvert
Concrete
Length
43 ft
2 main spans
Daily traffic
6,768
2023 count
Owner
State
State Highway Agency

About this bridge

KY-18 over Allen Fork is a concrete culvert carrying KY-18 over Allen Fork in Boone County, Kentucky. It was built in 1958, so it is 67 years old, older than the Kentucky average of 46.6 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 6,768 vehicles a day, roughly 22% of them trucks, projected to reach 6,768 by 2043. The structure is 43 ft (13.1 m) long. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesKY-18
CrossesAllen Fork
Location1.2 MI West of JCT Ky 338
RouteState Highway 18
CountyBoone County
StateKentucky
Coordinates39.02833, -84.74694
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 protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating60 US tons
Inventory rating45 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadH 20
Structure length43 ft (13.1 m)
Longest span20 ft (6.1 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,768 (2023)
Projected traffic6,768 by 2043
Trucks22%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was KY-18 over Allen Fork built?

It was built in 1958, making it 67 years old in 2025.

What condition is KY-18 over Allen Fork 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 2023.

How much traffic does KY-18 over Allen Fork carry?

About 6,768 vehicles per day (2023 count), of which roughly 22% are trucks.

How long is KY-18 over Allen Fork?

The structure is 43 ft (13.1 m) long with a longest span of 20 ft (6.1 m).

Who owns KY-18 over Allen Fork?

It is owned by the State Highway Agency.