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Nj 173 over Nj 31

Hunterdon County, New Jersey · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

Nj 173 over Nj 31 in Hunterdon County, New Jersey, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1967, making it 58 years old at the 2025 inventory.
It carries about 10,657 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 272 of the 373 inventoried bridges in Hunterdon County rated fair (72.9%); 26 (7.0%) are rated poor.
A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.

Component ratings


Structure	Steel stringer or multi-beam girder
Length	about 109 ft
Location	.2 Mi. N.of I-78 Exit 16
NBI structure number	1004153
Condition class	Fair

Source: FHWA National Bridge Inventory, 2025 data as reported by the New Jersey department of transportation.

Bridge	Built	Vehicles/day	Condition
I-78 EB over US 22 WB	1968	661,439	Fair
Rte I-78 & Ramp R over Beaver Brook	1948	130,244	Fair
I-78 over Beaver Brook	1941	130,244	Poor
I-78 over Branch Rockaway Creek	1966	129,446	Fair
I-78 EB over Beaver Brook	1958	109,955	Fair
I-78 over Tunnel Road	1960	108,465	Fair