US Bridges

Allen Road over Spring Brook

Fair

Somerset County, New Jersey · 1.28 MI W of CR 525 · Structure no. 18F1108

Built
1996
29 years old
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
85 ft
1 main span
Daily traffic
6,902
2023 count
Owner
County
County Highway Agency

About this bridge

Allen Road over Spring Brook is a steel stringer/multi-beam or girder carrying Allen Road over Spring Brook in Somerset County, New Jersey. It was built in 1996, so it is 29 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 6,902 vehicles a day, roughly 3% of them trucks, projected to reach 8,282 by 2043. The structure is 85 ft (25.9 m) long and 39 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesAllen Road
CrossesSpring Brook
Location1.28 MI W of CR 525
RouteCounty Highway 652
CountySomerset County
StateNew Jersey
Coordinates40.65401, -74.59652
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating66 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length85 ft (25.9 m)
Longest span82 ft (25 m)
Deck width39 ft (11.9 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,902 (2023)
Projected traffic8,282 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$109,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Allen Road over Spring Brook built?

It was built in 1996, making it 29 years old in 2025.

What condition is Allen Road over Spring 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 Allen Road over Spring Brook carry?

About 6,902 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Allen Road over Spring Brook?

The structure is 85 ft (25.9 m) long with a longest span of 82 ft (25 m) and a deck 39 ft wide.

Who owns Allen Road over Spring Brook?

It is owned by the County Highway Agency.