US Bridges

Alpine Road over US 20 By-Pass

Fair

Winnebago County, Illinois · South Edge Rockford · Structure no. 101015100000000

Built
1984
41 years old
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
213 ft
2 main spans
Daily traffic
21,400
2022 count
Owner
State
State Highway Agency

About this bridge

Alpine Road over US 20 By-Pass is a prestressed concrete continuous stringer/multi-beam or girder carrying Alpine Road over US 20 By-Pass in Winnebago County, Illinois. It was built in 1984, so it is 41 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 21,400 vehicles a day, roughly 10% of them trucks, projected to reach 25,553 by 2046. The structure is 213 ft (64.8 m) long and 89 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesAlpine Road
CrossesUS 20 By-Pass
LocationSouth Edge Rockford
CountyWinnebago County
StateIllinois
Coordinates42.22006, -89.02876
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
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 rating66.5 US tons
Inventory rating39.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 20
Structure length213 ft (64.8 m)
Longest span82 ft (24.9 m)
Deck width89 ft (27.1 m)
Roadway width78 ft (23.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,400 (2022)
Projected traffic25,553 by 2046
Trucks10%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.9 mi (3 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 Alpine Road over US 20 By-Pass built?

It was built in 1984, making it 41 years old in 2025.

What condition is Alpine Road over US 20 By-Pass 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 March 2023.

How much traffic does Alpine Road over US 20 By-Pass carry?

About 21,400 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is Alpine Road over US 20 By-Pass?

The structure is 213 ft (64.8 m) long with a longest span of 82 ft (24.9 m) and a deck 89 ft wide.

Who owns Alpine Road over US 20 By-Pass?

It is owned by the State Highway Agency.