US Bridges

US 421 over Little Flat Creek

Good

Franklin County, Kentucky · 3.9 MI N of Ky 12 · Structure no. 037B00106N

Built
2016
9 years old
Condition
Good
inspected July 2024
Type
Culvert
Aluminum, Wrought Iron, or Cast Iron
Length
38 ft
1 main span
Daily traffic
787
2019 count
Owner
State
State Highway Agency

About this bridge

US 421 over Little Flat Creek is a aluminum, wrought iron, or cast iron culvert carrying US 421 over Little Flat Creek in Franklin County, Kentucky. It was built in 2016, so it is 9 years old, younger than the Kentucky average of 46.6 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 787 vehicles a day, roughly 12% of them trucks, projected to reach 787 by 2039. The structure is 38 ft (11.6 m) long and 104 ft wide. If it were closed, the detour would be 19.3 mi (31 km).

CarriesUS 421
CrossesLittle Flat Creek
Location3.9 MI N of Ky 12
RouteU.S. Route 421
Coordinates38.32167, -84.94889
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating106 US tons
Inventory rating81.8 US tons

Structure

Structure typeCulvert
MaterialAluminum, Wrought Iron, or Cast Iron
DeckNot applicable
Main spans1
Design loadGreater than HL 93
Structure length38 ft (11.6 m)
Longest span38 ft (11.6 m)
Deck width104 ft (31.7 m)
Roadway width25 ft (7.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic787 (2019)
Projected traffic787 by 2039
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.3 mi (31 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 421 over Little Flat Creek built?

It was built in 2016, making it 9 years old in 2025.

What condition is US 421 over Little Flat Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2024.

How much traffic does US 421 over Little Flat Creek carry?

About 787 vehicles per day (2019 count), of which roughly 12% are trucks.

How long is US 421 over Little Flat Creek?

The structure is 38 ft (11.6 m) long with a longest span of 38 ft (11.6 m) and a deck 104 ft wide.

Who owns US 421 over Little Flat Creek?

It is owned by the State Highway Agency.