US Bridges

Ill 251 N B over Rockton Road

Fair

Winnebago County, Illinois · 2.6 MI S Ill 75 · Structure no. 101003200000000

Built
1967
58 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
192 ft
2 main spans
Daily traffic
16,600
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 251 N B over Rockton Road is a prestressed concrete continuous stringer/multi-beam or girder carrying Ill 251 N B over Rockton Road in Winnebago County, Illinois. It was built in 1967, so it is 58 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 5 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 16,600 vehicles a day, roughly 5% of them trucks, projected to reach 8,636 by 2046. The structure is 192 ft (58.5 m) long and 36 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesIll 251 N B
CrossesRockton Road
Location2.6 MI S Ill 75
RouteState Highway 251
CountyWinnebago County
StateIllinois
Coordinates42.45627, -89.01959
Functional classUrban Other Principal 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating57.1 US tons
Inventory rating34 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 20 + Mod
Structure length192 ft (58.5 m)
Longest span59 ft (18 m)
Deck width36 ft (10.9 m)
Roadway width32 ft (9.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,600 (2023)
Projected traffic8,636 by 2046
Trucks5%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

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 Ill 251 N B over Rockton Road built?

It was built in 1967, making it 58 years old in 2025.

What condition is Ill 251 N B over Rockton Road 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 June 2024.

How much traffic does Ill 251 N B over Rockton Road carry?

About 16,600 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Ill 251 N B over Rockton Road?

The structure is 192 ft (58.5 m) long with a longest span of 59 ft (18 m) and a deck 36 ft wide.

Who owns Ill 251 N B over Rockton Road?

It is owned by the State Highway Agency.