US Bridges

Old Stirling Road over Route I-78

Fair

Somerset County, New Jersey · 8.2 MI East of I-287 · Structure no. 1817173

Built
1965
60 years old, rebuilt 1993
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
214 ft
3 main spans
Daily traffic
7,020
2023 count
Owner
State
State Highway Agency

About this bridge

Old Stirling Road over Route I-78 is a prestressed concrete stringer/multi-beam or girder carrying Old Stirling Road over Route I-78 in Somerset County, New Jersey. It was built in 1965 and reconstructed in 1993, so it is 60 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 7,020 vehicles a day, roughly 1% of them trucks, projected to reach 8,530 by 2043. The structure is 214 ft (65.2 m) long and 45 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesOld Stirling Road
CrossesRoute I-78
Location8.2 MI East of I-287
CountySomerset County
StateNew Jersey
Coordinates40.64813, -74.4916
Functional classUrban Local

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 inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating79 US tons
Inventory rating34 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length214 ft (65.2 m)
Longest span84 ft (25.6 m)
Deck width45 ft (13.6 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deck100 ft (30.5 m)

Traffic and service

Average daily traffic7,020 (2023)
Projected traffic8,530 by 2043
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed3.1 mi (5 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$1.7 million (2023 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Old Stirling Road over Route I-78 built?

It was built in 1965, making it 60 years old in 2025. It was reconstructed in 1993.

What condition is Old Stirling Road over Route 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 February 2023.

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

About 7,020 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is Old Stirling Road over Route I-78?

The structure is 214 ft (65.2 m) long with a longest span of 84 ft (25.6 m) and a deck 45 ft wide.

Who owns Old Stirling Road over Route I-78?

It is owned by the State Highway Agency.