Structure 1817179 · Somerset County, NJ

I-78 EB over Plainfield Ave&green Brk

Carries I-78 EB over Plainfield Ave&green Brk, 1.79 Mi East Of CR 531.

Overall conditionFair

Set by its lowest-rated component: Substructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT648 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

648 ft end to end, longest span 118 ft: about 1.8 football fields. Lengths and the semi-truck 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.

Built196660 years old
Length648.0 ft197.5 m
Daily traffic51,186counted 2024
Last inspectedAugust 2024every 24 months

Location

StateNew Jersey
CountySomerset
Location1.79 Mi East Of CR 531
CarriesI-78 EB
CrossesPlainfield Ave&green Brk
Coordinates40.66209, -74.42633

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length648.0 ft (197.5 m)
Max Span118.1 ft (36 m)
Deck Width49.9 ft (15.2 m)
Deck Area3,002 sq m
Main Spans6
Year Built1966

Traffic

Avg Daily Traffic51,186 (2024)
Truck Traffic9%
Lanes On Bridge3
Lanes Under Bridge4

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number1817179

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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