US Bridges

Poplar Grove RD over US 20 Br

Fair

Boone County, Illinois · NE of Belvidere · Structure no. 004001500000000

Built
1986
39 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
242 ft
2 main spans
Daily traffic
3,600
2023 count
Owner
State
State Highway Agency

About this bridge

Poplar Grove RD over US 20 Br is a steel continuous stringer/multi-beam or girder carrying Poplar Grove RD over US 20 Br in Boone County, Illinois. It was built in 1986, so it is 39 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 3,600 vehicles a day, roughly 4% of them trucks, projected to reach 5,096 by 2046. The structure is 242 ft (73.7 m) long and 33 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesPoplar Grove RD
CrossesUS 20 Br
LocationNE of Belvidere
CountyBoone County
StateIllinois
Coordinates42.27452, -88.82254
Functional classUrban 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating64.3 US tons
Inventory rating37.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length242 ft (73.7 m)
Longest span122 ft (37.1 m)
Deck width33 ft (10.1 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,600 (2023)
Projected traffic5,096 by 2046
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 Poplar Grove RD over US 20 Br built?

It was built in 1986, making it 39 years old in 2025.

What condition is Poplar Grove RD over US 20 Br 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 August 2024.

How much traffic does Poplar Grove RD over US 20 Br carry?

About 3,600 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Poplar Grove RD over US 20 Br?

The structure is 242 ft (73.7 m) long with a longest span of 122 ft (37.1 m) and a deck 33 ft wide.

Who owns Poplar Grove RD over US 20 Br?

It is owned by the State Highway Agency.