US Bridges

I-78 over Tunnel Road

Fair

Hunterdon County, New Jersey · 0.44 MI South of Nj 173. · Structure no. 1014160

Built
1960
65 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
130 ft
2 main spans
Daily traffic
108,465
2024 count
Owner
State
State Highway Agency

About this bridge

I-78 over Tunnel Road is a prestressed concrete stringer/multi-beam or girder carrying I-78 over Tunnel Road in Hunterdon County, New Jersey. It was built in 1960, so it is 65 years old, older 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 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 108,465 vehicles a day, roughly 14% of them trucks, projected to reach 130,155 by 2044. The structure is 130 ft (39.6 m) long and 119 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesI-78
CrossesTunnel Road
Location0.44 MI South of Nj 173.
RouteInterstate 78
CountyHunterdon County
StateNew Jersey
Coordinates40.65126, -75.03476
Functional classRural Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.9 US tons
Inventory rating32 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2 (+1 approach)
Design loadHS 20
Structure length130 ft (39.6 m)
Longest span68 ft (20.7 m)
Deck width119 ft (36.4 m)
Roadway width112 ft (34.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic108,465 (2024)
Projected traffic130,155 by 2044
Trucks14%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-78 over Tunnel Road built?

It was built in 1960, making it 65 years old in 2025.

What condition is I-78 over Tunnel Road 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 September 2024.

How much traffic does I-78 over Tunnel Road carry?

About 108,465 vehicles per day (2024 count), of which roughly 14% are trucks.

How long is I-78 over Tunnel Road?

The structure is 130 ft (39.6 m) long with a longest span of 68 ft (20.7 m) and a deck 119 ft wide.

Who owns I-78 over Tunnel Road?

It is owned by the State Highway Agency.