US Bridges

Delta Drive over I-93 US 4

Poor

Merrimack County, New Hampshire · .6 MI North of Jct. US 4 · Structure no. 005201420011600

Built
1958
67 years old
Condition
Poor
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
192 ft
4 main spans
Daily traffic
612
2023 count
Owner
State
State Highway Agency

About this bridge

Delta Drive over I-93 US 4 is a steel continuous stringer/multi-beam or girder carrying Delta Drive over I-93 US 4 in Merrimack County, New Hampshire. It was built in 1958, so it is 67 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 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.

It carries about 612 vehicles a day, roughly 4% of them trucks, projected to reach 905 by 2043. The structure is 192 ft (58.5 m) long and 37 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesDelta Drive
CrossesI-93 US 4
Location.6 MI North of Jct. US 4
RouteCity Street 0
CountyMerrimack County
StateNew Hampshire
Coordinates43.22369, -71.53454
Functional classUrban 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
Deck3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 8 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.7 US tons
Inventory rating16.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length192 ft (58.5 m)
Longest span58 ft (17.7 m)
Deck width37 ft (11.3 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic612 (2023)
Projected traffic905 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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$314,000 (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Delta Drive over I-93 US 4 built?

It was built in 1958, making it 67 years old in 2025.

What condition is Delta Drive over I-93 US 4 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 November 2024.

How much traffic does Delta Drive over I-93 US 4 carry?

About 612 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Delta Drive over I-93 US 4?

The structure is 192 ft (58.5 m) long with a longest span of 58 ft (17.7 m) and a deck 37 ft wide.

Who owns Delta Drive over I-93 US 4?

It is owned by the State Highway Agency.