US Bridges

Old County RD N over Collins Brook

Poor

Hillsborough County, New Hampshire · 2.4 Mi. Deering Tl · Structure no. 008600910014200

Built
1981
44 years old
Condition
Poor
inspected October 2024
Type
Culvert
Steel
Length
30 ft
2 main spans
Daily traffic
96
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Old County RD N over Collins Brook is a steel culvert carrying Old County RD N over Collins Brook in Hillsborough County, New Hampshire. It was built in 1981, so it is 44 years old, younger than the New Hampshire average of 56.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: open, temporary structure in place while original is closed.

It carries about 96 vehicles a day, projected to reach 142 by 2043. The structure is 30 ft (9.1 m) long. If it were closed, the detour would be 6.8 mi (11 km).

Location

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CarriesOld County RD N
CrossesCollins Brook
Location2.4 Mi. Deering Tl
CountyHillsborough County
StateNew Hampshire
Coordinates43.01217, -71.82992
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Culvert3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Last inspectionOctober 2024
Inspection intervalevery 16 months
Operating statusOpen, temporary structure in place while original is closed
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating0 US tons
Inventory rating0 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans2
Design loadUnknown
Structure length30 ft (9.1 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic96 (2023)
Projected traffic142 by 2043
Trucks0%
Lanes on structure2
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Old County RD N over Collins Brook built?

It was built in 1981, making it 44 years old in 2025.

What condition is Old County RD N over Collins Brook in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2024.

How much traffic does Old County RD N over Collins Brook carry?

About 96 vehicles per day (2023 count).

How long is Old County RD N over Collins Brook?

The structure is 30 ft (9.1 m) long with a longest span of 12 ft (3.7 m).

Who owns Old County RD N over Collins Brook?

It is owned by the City or Municipal Highway Agency.