US Bridges

Al - 4 (us 78) over Coosa River

Fair

St. Clair County, Alabama · @ ST Clair/Talladega Cl · Structure no. 010641

Built
1930
95 years old, rebuilt 1972
Condition
Fair
inspected August 2024
Type
Truss - Thru
Steel
Length
917 ft
3 main spans
Daily traffic
6,426
2024 count
Owner
State
State Highway Agency

About this bridge

Al - 4 (us 78) over Coosa River is a steel truss - thru carrying Al - 4 (us 78) over Coosa River in St. Clair County, Alabama. It was built in 1930 and reconstructed in 1972, so it is 95 years old, older than the Alabama average of 51.1 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 6,426 vehicles a day, roughly 3% of them trucks, projected to reach 11,608 by 2044. The structure is 917 ft (279.5 m) long and 23 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesAl - 4 (us 78)
CrossesCoosa River
Location@ ST Clair/Talladega Cl
RouteU.S. Route 78
CountySt. Clair County
StateAlabama
Coordinates33.60188, -86.19662
Functional classRural Major 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 inspectionAugust 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 geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating52.5 US tons
Inventory rating31.5 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans3 (+12 approach)
Design loadH 15
Structure length917 ft (279.5 m)
Longest span232 ft (70.7 m)
Deck width23 ft (7.1 m)
Roadway width20 ft (6 m)
Vertical clearance over deck14 ft (4.2 m)

Traffic and service

Average daily traffic6,426 (2024)
Projected traffic11,608 by 2044
Trucks3%
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 statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$4.8 million (2025 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Al - 4 (us 78) over Coosa River built?

It was built in 1930, making it 95 years old in 2025. It was reconstructed in 1972.

What condition is Al - 4 (us 78) over Coosa River 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 August 2024.

How much traffic does Al - 4 (us 78) over Coosa River carry?

About 6,426 vehicles per day (2024 count), of which roughly 3% are trucks.

How long is Al - 4 (us 78) over Coosa River?

The structure is 917 ft (279.5 m) long with a longest span of 232 ft (70.7 m) and a deck 23 ft wide.

Who owns Al - 4 (us 78) over Coosa River?

It is owned by the State Highway Agency.