US Bridges

Il 78 over I-88

Fair

Whiteside County, Illinois · 2 MI W Lyndon · Structure no. 098006500000000

Built
1974
51 years old, rebuilt 2024
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
256 ft
2 main spans
Daily traffic
1,800
2023 count
Owner
State
State Highway Agency

About this bridge

Il 78 over I-88 is a steel continuous stringer/multi-beam or girder carrying Il 78 over I-88 in Whiteside County, Illinois. It was built in 1974 and reconstructed in 2024, so it is 51 years old, older 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 1,800 vehicles a day, roughly 11% of them trucks, projected to reach 2,475 by 2046. The structure is 256 ft (78 m) long and 68 ft wide. If it were closed, the detour would be 21.1 mi (34 km).

Location

Open in Google Maps
CarriesIl 78
CrossesI-88
Location2 MI W Lyndon
RouteState Highway 78
CountyWhiteside County
StateIllinois
Coordinates41.72219, -89.96713
Functional classRural Minor Arterial

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.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52.1 US tons
Inventory rating40.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 20 + Mod
Structure length256 ft (78 m)
Longest span110 ft (33.5 m)
Deck width68 ft (20.7 m)
Roadway width51 ft (15.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,800 (2023)
Projected traffic2,475 by 2046
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed21.1 mi (34 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Il 78 over I-88 built?

It was built in 1974, making it 51 years old in 2025. It was reconstructed in 2024.

What condition is Il 78 over I-88 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 November 2024.

How much traffic does Il 78 over I-88 carry?

About 1,800 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is Il 78 over I-88?

The structure is 256 ft (78 m) long with a longest span of 110 ft (33.5 m) and a deck 68 ft wide.

Who owns Il 78 over I-88?

It is owned by the State Highway Agency.