US Bridges

Saw Mill Road over Route I-78

Fair

Somerset County, New Jersey · 8 MI East of I-287 · Structure no. 1817172

Built
1965
60 years old
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
247 ft
4 main spans
Daily traffic
2,851
2023 count
Owner
State
State Highway Agency

About this bridge

Saw Mill Road over Route I-78 is a prestressed concrete stringer/multi-beam or girder carrying Saw Mill Road over Route I-78 in Somerset County, New Jersey. It was built in 1965, 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 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 2,851 vehicles a day, roughly 1% of them trucks, projected to reach 3,421 by 2043. The structure is 247 ft (75.3 m) long and 45 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSaw Mill Road
CrossesRoute I-78
Location8 MI East of I-287
CountySomerset County
StateNew Jersey
Coordinates40.64694, -74.49722
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 alignment6: Equal to present minimum criteria
Operating rating93 US tons
Inventory rating39 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length247 ft (75.3 m)
Longest span94 ft (28.7 m)
Deck width45 ft (13.6 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,851 (2023)
Projected traffic3,421 by 2043
Trucks1%
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$2.2 million (2023 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Saw Mill Road over Route I-78 built?

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

What condition is Saw Mill 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 Saw Mill Road over Route I-78 carry?

About 2,851 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is Saw Mill Road over Route I-78?

The structure is 247 ft (75.3 m) long with a longest span of 94 ft (28.7 m) and a deck 45 ft wide.

Who owns Saw Mill Road over Route I-78?

It is owned by the State Highway Agency.