US Bridges

FM 486 over Alligator Slough

Fair

Milam County, Texas · 2.3 MI SW of FM 487 · Structure no. 171660033705011

Built
1951
74 years old
Condition
Fair
inspected September 2024
Type
Culvert
Concrete
Length
27 ft
4 main spans
Daily traffic
1,005
2023 count
Owner
State
State Highway Agency

About this bridge

FM 486 over Alligator Slough is a concrete culvert carrying FM 486 over Alligator Slough in Milam County, Texas. It was built in 1951, so it is 74 years old, older than the Texas average of 44.4 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 1,005 vehicles a day, roughly 13% of them trucks, projected to reach 1,648 by 2042. The structure is 27 ft (8.2 m) long. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesFM 486
CrossesAlligator Slough
Location2.3 MI SW of FM 487
RouteState Highway 486
CountyMilam County
StateTexas
Coordinates30.7165, -97.14444
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
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44 US tons
Inventory rating26 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans4
Design loadOther
Structure length27 ft (8.2 m)
Longest span6 ft (1.8 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,005 (2023)
Projected traffic1,648 by 2042
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM 486 over Alligator Slough built?

It was built in 1951, making it 74 years old in 2025.

What condition is FM 486 over Alligator Slough 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 September 2024.

How much traffic does FM 486 over Alligator Slough carry?

About 1,005 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is FM 486 over Alligator Slough?

The structure is 27 ft (8.2 m) long with a longest span of 6 ft (1.8 m).

Who owns FM 486 over Alligator Slough?

It is owned by the State Highway Agency.