US Bridges

Harris Road over Salmon Brook

Fair

Hillsborough County, New Hampshire · .1 MI W of E Dunstable RD · Structure no. 017701210007100

Built
1955
70 years old
Condition
Fair
inspected August 2023
Type
Culvert
Concrete
Length
22 ft
1 main span
Daily traffic
13,964
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Harris Road over Salmon Brook is a concrete culvert carrying Harris Road over Salmon Brook in Hillsborough County, New Hampshire. It was built in 1955, so it is 70 years old, older than the New Hampshire average of 56.9 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 13,964 vehicles a day, roughly 3% of them trucks, projected to reach 20,666 by 2043. The structure is 22 ft (6.7 m) long. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesHarris Road
CrossesSalmon Brook
Location.1 MI W of E Dunstable RD
RouteCity Street 0
CountyHillsborough County
StateNew Hampshire
Coordinates42.73176, -71.47237
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 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
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.6 US tons
Inventory rating31.9 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadH 20
Structure length22 ft (6.7 m)
Longest span20 ft (6.1 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,964 (2023)
Projected traffic20,666 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 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 Harris Road over Salmon Brook built?

It was built in 1955, making it 70 years old in 2025.

What condition is Harris Road over Salmon 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 August 2023.

How much traffic does Harris Road over Salmon Brook carry?

About 13,964 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Harris Road over Salmon Brook?

The structure is 22 ft (6.7 m) long with a longest span of 20 ft (6.1 m).

Who owns Harris Road over Salmon Brook?

It is owned by the City or Municipal Highway Agency.