US Bridges

Al 171 over Unknown Branch

Fair

Tuscaloosa County, Alabama · 1.5 MI N Mt Olive RD · Structure no. 012226

Built
1979
46 years old
Condition
Fair
inspected February 2024
Type
Channel Beam
Concrete
Length
68 ft
4 main spans
Daily traffic
3,360
2017 count
Owner
State
State Highway Agency

About this bridge

Al 171 over Unknown Branch is a concrete channel beam carrying Al 171 over Unknown Branch in Tuscaloosa County, Alabama. It was built in 1979, so it is 46 years old, younger 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 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: open, would be posted or closed except for temporary shoring.

It carries about 3,360 vehicles a day, roughly 10% of them trucks, projected to reach 4,376 by 2041. The structure is 68 ft (20.7 m) long and 28 ft wide. If it were closed, the detour would be 19.3 mi (31 km).

Location

Open in Google Maps
CarriesAl 171
CrossesUnknown Branch
Location1.5 MI N Mt Olive RD
RouteState Highway 171
CountyTuscaloosa County
StateAlabama
Coordinates33.32383, -87.657
Functional classRural Minor Arterial

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 inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, would be posted or closed except for temporary shoring
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to 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 rating47.7 US tons
Inventory rating28.5 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, precast panels
Main spans4
Design loadH 15
Structure length68 ft (20.7 m)
Longest span34 ft (10.4 m)
Deck width28 ft (8.6 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,360 (2017)
Projected traffic4,376 by 2041
Trucks10%
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$601,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Al 171 over Unknown Branch built?

It was built in 1979, making it 46 years old in 2025.

What condition is Al 171 over Unknown Branch 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 Al 171 over Unknown Branch carry?

About 3,360 vehicles per day (2017 count), of which roughly 10% are trucks.

How long is Al 171 over Unknown Branch?

The structure is 68 ft (20.7 m) long with a longest span of 34 ft (10.4 m) and a deck 28 ft wide.

Who owns Al 171 over Unknown Branch?

It is owned by the State Highway Agency.