US Bridges

Il 171 SB over RR - BNSF

Fair

Cook County, Illinois · 1.0 M W of I-55 · Structure no. 016245500000000

Built
1964
61 years old, rebuilt 2015
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
378 ft
4 main spans
Daily traffic
40,100
2023 count
Owner
State
State Highway Agency

About this bridge

Il 171 SB over RR - BNSF is a steel continuous stringer/multi-beam or girder carrying Il 171 SB over RR - BNSF in Cook County, Illinois. It was built in 1964 and reconstructed in 2015, so it is 61 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 40,100 vehicles a day, roughly 9% of them trucks, projected to reach 19,443 by 2046. The structure is 378 ft (115.2 m) long and 50 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesIl 171 SB
CrossesRR - BNSF
Location1.0 M W of I-55
RouteState Highway 171
CountyCook County
StateIllinois
Coordinates41.79623, -87.82853
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
Deck8 Very GoodNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating66 US tons
Inventory rating39.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length378 ft (115.2 m)
Longest span120 ft (36.6 m)
Deck width50 ft (15.2 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40,100 (2023)
Projected traffic19,443 by 2046
Trucks9%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed5 mi (8 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Il 171 SB over RR - BNSF built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 2015.

What condition is Il 171 SB over RR - BNSF 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 December 2023.

How much traffic does Il 171 SB over RR - BNSF carry?

About 40,100 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is Il 171 SB over RR - BNSF?

The structure is 378 ft (115.2 m) long with a longest span of 120 ft (36.6 m) and a deck 50 ft wide.

Who owns Il 171 SB over RR - BNSF?

It is owned by the State Highway Agency.