US Bridges

US0171 over Bayou San Miguel

Fair

Sabine Parish, Louisiana · 2.68 Mi. South of LA 1218 · Structure no. 084300250312592

Built
1963
62 years old
Condition
Fair
inspected October 2024
Type
Slab
Concrete
Length
200 ft
10 main spans
Daily traffic
4,790
2021 count
Owner
State
State Highway Agency

About this bridge

US0171 over Bayou San Miguel is a concrete slab carrying US0171 over Bayou San Miguel in Sabine Parish, Louisiana. It was built in 1963, so it is 62 years old, older than the Louisiana average of 43 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 4,790 vehicles a day, roughly 15% of them trucks, projected to reach 5,269 by 2041. The structure is 200 ft (61 m) long and 33 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesUS0171
CrossesBayou San Miguel
Location2.68 Mi. South of LA 1218
RouteU.S. Route 171
CountySabine Parish
StateLouisiana
Coordinates31.65584, -93.65767
Functional classRural Principal Arterial - Other

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 inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating23.9 US tons
Inventory rating18.5 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans10
Design loadHS 20
Structure length200 ft (61 m)
Longest span20 ft (6.1 m)
Deck width33 ft (10.2 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,790 (2021)
Projected traffic5,269 by 2041
Trucks15%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$897,000
NavigationNo navigation control on waterway

Frequently asked questions

When was US0171 over Bayou San Miguel built?

It was built in 1963, making it 62 years old in 2025.

What condition is US0171 over Bayou San Miguel 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 October 2024.

How much traffic does US0171 over Bayou San Miguel carry?

About 4,790 vehicles per day (2021 count), of which roughly 15% are trucks.

How long is US0171 over Bayou San Miguel?

The structure is 200 ft (61 m) long with a longest span of 20 ft (6.1 m) and a deck 33 ft wide.

Who owns US0171 over Bayou San Miguel?

It is owned by the State Highway Agency.