US Bridges

Rock Ave (cr 645) over Green Brook

Fair

Somerset County, New Jersey · 0.64 MI S of US 22 · Structure no. 18L0905

Built
1980
45 years old
Condition
Fair
inspected October 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
88 ft
2 main spans
Daily traffic
13,785
2023 count
Owner
County
County Highway Agency

About this bridge

Rock Ave (cr 645) over Green Brook is a prestressed concrete box beam or girders - multiple carrying Rock Ave (cr 645) over Green Brook in Somerset County, New Jersey. It was built in 1980, so it is 45 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 13,785 vehicles a day, roughly 4% of them trucks, projected to reach 16,820 by 2043. The structure is 88 ft (26.8 m) long and 58 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesRock Ave (cr 645)
CrossesGreen Brook
Location0.64 MI S of US 22
RouteCounty Highway 645
CountySomerset County
StateNew Jersey
Coordinates40.60218, -74.45719
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.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68 US tons
Inventory rating38 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length88 ft (26.8 m)
Longest span40 ft (12.2 m)
Deck width58 ft (17.8 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,785 (2023)
Projected traffic16,820 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Rock Ave (cr 645) over Green Brook built?

It was built in 1980, making it 45 years old in 2025.

What condition is Rock Ave (cr 645) over Green Brook 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 October 2023.

How much traffic does Rock Ave (cr 645) over Green Brook carry?

About 13,785 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Rock Ave (cr 645) over Green Brook?

The structure is 88 ft (26.8 m) long with a longest span of 40 ft (12.2 m) and a deck 58 ft wide.

Who owns Rock Ave (cr 645) over Green Brook?

It is owned by the County Highway Agency.