US Bridges

I 20 over Slough

Good

Newton County, Mississippi · 1.7 MI E US 80 · Structure no. 110002005110300

Built
1966
59 years old
Condition
Good
inspected February 2023
Type
Culvert
Concrete
Length
30 ft
2 main spans
Daily traffic
20,000
2023 count
Owner
State
State Highway Agency

About this bridge

I 20 over Slough is a concrete culvert carrying I 20 over Slough in Newton County, Mississippi. It was built in 1966, so it is 59 years old, older than the Mississippi average of 38.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 20,000 vehicles a day, roughly 45% of them trucks, projected to reach 20,000 by 2043. The structure is 30 ft (9.1 m) long. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI 20
CrossesSlough
Location1.7 MI E US 80
RouteInterstate 20
CountyNewton County
StateMississippi
Coordinates32.34005, -89.26067
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert8 Very GoodNo problems noted.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating65.5 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span14 ft (4.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20,000 (2023)
Projected traffic20,000 by 2043
Trucks45%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 20 over Slough built?

It was built in 1966, making it 59 years old in 2025.

What condition is I 20 over Slough in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2023.

How much traffic does I 20 over Slough carry?

About 20,000 vehicles per day (2023 count), of which roughly 45% are trucks.

How long is I 20 over Slough?

The structure is 30 ft (9.1 m) long with a longest span of 14 ft (4.3 m).

Who owns I 20 over Slough?

It is owned by the State Highway Agency.