US Bridges

Stirling Road over I-78

Fair

Somerset County, New Jersey · 2.36 MI E of 287 Exit 36 · Structure no. 1817174

Built
1970
55 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
207 ft
3 main spans
Daily traffic
9,840
2024 count
Owner
State
State Highway Agency

About this bridge

Stirling Road over I-78 is a prestressed concrete stringer/multi-beam or girder carrying Stirling Road over I-78 in Somerset County, New Jersey. It was built in 1970, so it is 55 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 9,840 vehicles a day, roughly 4% of them trucks, projected to reach 11,790 by 2044. The structure is 207 ft (63.1 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesStirling Road
CrossesI-78
Location2.36 MI E of 287 Exit 36
RouteCounty Highway 653
CountySomerset County
StateNew Jersey
Coordinates40.64911, -74.47775
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 inspectionJuly 2024
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 geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating49.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length207 ft (63.1 m)
Longest span81 ft (24.7 m)
Deck width44 ft (13.4 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,840 (2024)
Projected traffic11,790 by 2044
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 statusHistorical significance not determinable at this time
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$320,000 (2024 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Stirling Road over I-78 built?

It was built in 1970, making it 55 years old in 2025.

What condition is Stirling Road over I-78 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 July 2024.

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

About 9,840 vehicles per day (2024 count), of which roughly 4% are trucks.

How long is Stirling Road over I-78?

The structure is 207 ft (63.1 m) long with a longest span of 81 ft (24.7 m) and a deck 44 ft wide.

Who owns Stirling Road over I-78?

It is owned by the State Highway Agency.