US Bridges

US Rt 30 over Rock River

Fair

Whiteside County, Illinois · 1.5 MI W Rock Falls · Structure no. 098003400000000

Built
1940
85 years old, rebuilt 1990
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,097 ft
8 main spans
Daily traffic
4,900
2023 count
Owner
State
State Highway Agency

About this bridge

US Rt 30 over Rock River is a steel continuous stringer/multi-beam or girder carrying US Rt 30 over Rock River in Whiteside County, Illinois. It was built in 1940 and reconstructed in 1990, so it is 85 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 4,900 vehicles a day, roughly 13% of them trucks, projected to reach 4,646 by 2046. The structure is 1,097 ft (334.5 m) long and 43 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesUS Rt 30
CrossesRock River
Location1.5 MI W Rock Falls
RouteU.S. Route 30
CountyWhiteside County
StateIllinois
Coordinates41.77234, -89.74634
Functional classUrban 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.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 rating75.7 US tons
Inventory rating45.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadHS 20
Structure length1,097 ft (334.5 m)
Longest span143 ft (43.5 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,900 (2023)
Projected traffic4,646 by 2046
Trucks13%
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 US Rt 30 over Rock River built?

It was built in 1940, making it 85 years old in 2025. It was reconstructed in 1990.

What condition is US Rt 30 over Rock 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 September 2023.

How much traffic does US Rt 30 over Rock River carry?

About 4,900 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is US Rt 30 over Rock River?

The structure is 1,097 ft (334.5 m) long with a longest span of 143 ft (43.5 m) and a deck 43 ft wide.

Who owns US Rt 30 over Rock River?

It is owned by the State Highway Agency.