US Bridges

Experiment ST Road over I 20

Good

Newton County, Mississippi · 3.5 MI E SR 15 · Structure no. 41000200511128A

Built
1961
64 years old
Condition
Good
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
162 ft
3 main spans
Daily traffic
60
2023 count
Owner
State
State Highway Agency

About this bridge

Experiment ST Road over I 20 is a prestressed concrete stringer/multi-beam or girder carrying Experiment ST Road over I 20 in Newton County, Mississippi. It was built in 1961, so it is 64 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 60 vehicles a day, roughly 8% of them trucks, projected to reach 60 by 2043. The structure is 162 ft (49.4 m) long and 30 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesExperiment ST Road
CrossesI 20
Location3.5 MI E SR 15
RouteCounty Highway 0
CountyNewton County
StateMississippi
Coordinates32.34488, -89.08445
Functional classRural Local

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.1 US tons
Inventory rating63.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 15
Structure length162 ft (49.4 m)
Longest span67 ft (20.4 m)
Deck width30 ft (9.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60 (2023)
Projected traffic60 by 2043
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$242 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Experiment ST Road over I 20 built?

It was built in 1961, making it 64 years old in 2025.

What condition is Experiment ST Road over I 20 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 Experiment ST Road over I 20 carry?

About 60 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is Experiment ST Road over I 20?

The structure is 162 ft (49.4 m) long with a longest span of 67 ft (20.4 m) and a deck 30 ft wide.

Who owns Experiment ST Road over I 20?

It is owned by the State Highway Agency.