US Bridges

Nielson RD over Serpent Bayou

Fair

Allen Parish, Louisiana · 1.0 MI W of LA 99 · Structure no. 070230280924741

Built
2000
25 years old
Condition
Fair
inspected October 2023
Type
Slab
Concrete
Length
95 ft
5 main spans
Daily traffic
61
2020 count
Owner
County
County Highway Agency

About this bridge

Nielson RD over Serpent Bayou is a concrete slab carrying Nielson RD over Serpent Bayou in Allen Parish, Louisiana. It was built in 2000, so it is 25 years old, younger 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 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 61 vehicles a day, projected to reach 67 by 2040. The structure is 95 ft (29 m) long and 27 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesNielson RD
CrossesSerpent Bayou
Location1.0 MI W of LA 99
RouteCounty Highway 0
CountyAllen Parish
StateLouisiana
Coordinates30.46777, -92.79121
Functional classRural Local

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 inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating55.3 US tons
Inventory rating42.9 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans5
Design loadHS 20
Structure length95 ft (29 m)
Longest span19 ft (5.8 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic61 (2020)
Projected traffic67 by 2040
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Nielson RD over Serpent Bayou built?

It was built in 2000, making it 25 years old in 2025.

What condition is Nielson RD over Serpent Bayou 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 2023.

How much traffic does Nielson RD over Serpent Bayou carry?

About 61 vehicles per day (2020 count).

How long is Nielson RD over Serpent Bayou?

The structure is 95 ft (29 m) long with a longest span of 19 ft (5.8 m) and a deck 27 ft wide.

Who owns Nielson RD over Serpent Bayou?

It is owned by the County Highway Agency.