US Bridges

Nj 173 over Nj 31

Fair

Hunterdon County, New Jersey · .2 Mi. N.Of I-78 Exit 16 · Structure no. 1004153

Built
1967
58 years old
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
110 ft
2 main spans
Daily traffic
10,657
2023 count
Owner
State
State Highway Agency

About this bridge

Nj 173 over Nj 31 is a steel stringer/multi-beam or girder carrying Nj 173 over Nj 31 in Hunterdon County, New Jersey. It was built in 1967, so it is 58 years old, younger than the New Jersey average of 58.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 10,657 vehicles a day, roughly 4% of them trucks, projected to reach 12,788 by 2043. The structure is 110 ft (33.5 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNj 173
CrossesNj 31
Location.2 Mi. N.Of I-78 Exit 16
RouteState Highway 173
CountyHunterdon County
StateNew Jersey
Coordinates40.64117, -74.8968
Functional classUrban Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment6: Equal to present minimum criteria
Operating rating110.1 US tons
Inventory rating61 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length110 ft (33.5 m)
Longest span52 ft (15.8 m)
Deck width44 ft (13.4 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,657 (2023)
Projected traffic12,788 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$76,000 (2023 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Nj 173 over Nj 31 built?

It was built in 1967, making it 58 years old in 2025.

What condition is Nj 173 over Nj 31 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 February 2023.

How much traffic does Nj 173 over Nj 31 carry?

About 10,657 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Nj 173 over Nj 31?

The structure is 110 ft (33.5 m) long with a longest span of 52 ft (15.8 m) and a deck 44 ft wide.

Who owns Nj 173 over Nj 31?

It is owned by the State Highway Agency.