US Bridges

Griggstown Causwy over Millstone River

Fair

Somerset County, New Jersey · At CR 533 Intersection · Structure no. 18F0302

Built
1978
47 years old, rebuilt 2006
Condition
Fair
inspected September 2023
Type
Truss - Thru
Steel
Length
100 ft
2 main spans
Daily traffic
6,198
2023 count
Owner
County
County Highway Agency

About this bridge

Griggstown Causwy over Millstone River is a steel truss - thru carrying Griggstown Causwy over Millstone River in Somerset County, New Jersey. It was built in 1978 and reconstructed in 2006, so it is 47 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 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 6,198 vehicles a day, roughly 3% of them trucks, projected to reach 7,438 by 2043. The structure is 100 ft (30.5 m) long and 16 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesGriggstown Causwy
CrossesMillstone River
LocationAt CR 533 Intersection
RouteCounty Highway 632
CountySomerset County
StateNew Jersey
Coordinates40.43907, -74.61776
Functional classUrban Collector

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating110.1 US tons
Inventory rating72 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 25 or greater
Structure length100 ft (30.5 m)
Longest span49 ft (14.9 m)
Deck width16 ft (4.9 m)
Roadway width13 ft (4.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,198 (2023)
Projected traffic7,438 by 2043
Trucks3%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$3.4 million (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Griggstown Causwy over Millstone River built?

It was built in 1978, making it 47 years old in 2025. It was reconstructed in 2006.

What condition is Griggstown Causwy over Millstone River 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 2023.

How much traffic does Griggstown Causwy over Millstone River carry?

About 6,198 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Griggstown Causwy over Millstone River?

The structure is 100 ft (30.5 m) long with a longest span of 49 ft (14.9 m) and a deck 16 ft wide.

Who owns Griggstown Causwy over Millstone River?

It is owned by the County Highway Agency.