Structure 49019500000000 · Lake County, IL

Il 173 over Mill Creek

Carries Il 173 over Mill Creek, 0.3 M E Of US 45.

Overall conditionGood

Set by its lowest-rated component: Deck at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructure8/9 · Very Good
Substructure8/9 · Very Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT59 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9 · sets the ratingSuperstructure 8/9Substructure 8/9

59 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built200323 years old
Length59.1 ft18 m
Daily traffic15,600counted 2023
Last inspectedJanuary 2023every 48 months

Location

StateIllinois
CountyLake
Location0.3 M E Of US 45
CarriesIl 173
CrossesMill Creek
Coordinates42.46613, -88.00895

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length59.1 ft (18 m)
Max Span59.1 ft (18 m)
Deck Width42.7 ft (13 m)
Deck Area234 sq m
Main Spans1
Year Built2003

Traffic

Avg Daily Traffic15,600 (2023)
Truck Traffic5%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJanuary 2023
Inspection FrequencyEvery 48 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number049019500000000

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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