US Bridges

Ill 178 over Illinois River

Fair

LaSalle County, Illinois · 2.2 MI S of US 6 · Structure no. 050025600000000

Built
2020
5 years old
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,159 ft
3 main spans
Daily traffic
3,200
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 178 over Illinois River is a steel continuous stringer/multi-beam or girder carrying Ill 178 over Illinois River in LaSalle County, Illinois. It was built in 2020, so it is 5 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 3,200 vehicles a day, roughly 8% of them trucks, projected to reach 3,586 by 2046. The structure is 1,159 ft (353.4 m) long and 50 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesIll 178
CrossesIllinois River
Location2.2 MI S of US 6
RouteState Highway 178
CountyLaSalle County
StateIllinois
Coordinates41.3276, -89.01052
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
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection9 ExcellentNo problems noted.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating67.1 US tons
Inventory rating51.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length1,159 ft (353.4 m)
Longest span440 ft (134.1 m)
Deck width50 ft (15.2 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,200 (2023)
Projected traffic3,586 by 2046
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Ill 178 over Illinois River built?

It was built in 2020, making it 5 years old in 2025.

What condition is Ill 178 over Illinois River 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 Ill 178 over Illinois River carry?

About 3,200 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is Ill 178 over Illinois River?

The structure is 1,159 ft (353.4 m) long with a longest span of 440 ft (134.1 m) and a deck 50 ft wide.

Who owns Ill 178 over Illinois River?

It is owned by the State Highway Agency.