US Bridges

Carlson RD over Spring Creek

Fair

Boone County, Illinois · 3.0 MI S Garden Prai · Structure no. 004307700000000

Built
1984
41 years old
Condition
Fair
inspected March 2024
Type
Culvert
Concrete
Length
24 ft
2 main spans
Daily traffic
325
2023 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

Carlson RD over Spring Creek is a concrete culvert carrying Carlson RD over Spring Creek in Boone 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 325 vehicles a day, roughly 29% of them trucks, projected to reach 364 by 2046. The structure is 24 ft (7.3 m) long. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesCarlson RD
CrossesSpring Creek
Location3.0 MI S Garden Prai
RouteCounty Highway 0
CountyBoone County
StateIllinois
Coordinates42.21162, -88.71792
Functional classUrban Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length24 ft (7.3 m)
Longest span11 ft (3.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic325 (2023)
Projected traffic364 by 2046
Trucks29%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Carlson RD over Spring Creek built?

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

What condition is Carlson RD over Spring Creek 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 2024.

How much traffic does Carlson RD over Spring Creek carry?

About 325 vehicles per day (2023 count), of which roughly 29% are trucks.

How long is Carlson RD over Spring Creek?

The structure is 24 ft (7.3 m) long with a longest span of 11 ft (3.4 m).

Who owns Carlson RD over Spring Creek?

It is owned by the Town or Township Highway Agency.