US Bridges

Ill 78 over Trib E Fork Plum Riv

Fair

Carroll County, Illinois · 4 MI N Mt Carroll · Structure no. 008003500000000

Built
1990
35 years old
Condition
Fair
inspected August 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
70 ft
1 main span
Daily traffic
625
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 78 over Trib E Fork Plum Riv is a prestressed concrete box beam or girders - multiple carrying Ill 78 over Trib E Fork Plum Riv in Carroll County, Illinois. It was built in 1990, so it is 35 years old, younger than the Illinois average of 45.3 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 625 vehicles a day, roughly 19% of them trucks, projected to reach 657 by 2046. The structure is 70 ft (21.3 m) long and 30 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

Open in Google Maps
CarriesIll 78
CrossesTrib E Fork Plum Riv
Location4 MI N Mt Carroll
RouteState Highway 78
CountyCarroll County
StateIllinois
Coordinates42.16787, -89.98725
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73.5 US tons
Inventory rating45.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length70 ft (21.3 m)
Longest span65 ft (19.9 m)
Deck width30 ft (9.1 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic625 (2023)
Projected traffic657 by 2046
Trucks19%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.2 mi (26 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ill 78 over Trib E Fork Plum Riv built?

It was built in 1990, making it 35 years old in 2025.

What condition is Ill 78 over Trib E Fork Plum Riv 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 August 2023.

How much traffic does Ill 78 over Trib E Fork Plum Riv carry?

About 625 vehicles per day (2023 count), of which roughly 19% are trucks.

How long is Ill 78 over Trib E Fork Plum Riv?

The structure is 70 ft (21.3 m) long with a longest span of 65 ft (19.9 m) and a deck 30 ft wide.

Who owns Ill 78 over Trib E Fork Plum Riv?

It is owned by the State Highway Agency.