US Bridges

ST 1 a over HWY M Coughlin & Relie

Fair

Suffolk County, Massachusetts · 1.3 KM NE of Callahan Tun · Structure no. B1623639UDOTNBI

Built
1951
74 years old, rebuilt 1977
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
169 ft
2 main spans
Daily traffic
102,900
2024 count
Owner
State
State Highway Agency

About this bridge

ST 1 a over HWY M Coughlin & Relie is a steel stringer/multi-beam or girder carrying ST 1 a over HWY M Coughlin & Relie in Suffolk County, Massachusetts. It was built in 1951 and reconstructed in 1977, so it is 74 years old, older than the Massachusetts average of 63.8 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 102,900 vehicles a day, roughly 7% of them trucks, projected to reach 68,226 by 2033. The structure is 169 ft (51.5 m) long and 115 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesST 1 a
CrossesHWY M Coughlin & Relie
Location1.3 KM NE of Callahan Tun
RouteState Highway 1A
CountySuffolk County
StateMassachusetts
Coordinates42.37854, -71.02611
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating77.5 US tons
Inventory rating46.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length169 ft (51.5 m)
Longest span85 ft (25.9 m)
Deck width115 ft (35.1 m)
Roadway width110 ft (33.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic102,900 (2024)
Projected traffic68,226 by 2033
Trucks7%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$17.8 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was ST 1 a over HWY M Coughlin & Relie built?

It was built in 1951, making it 74 years old in 2025. It was reconstructed in 1977.

What condition is ST 1 a over HWY M Coughlin & Relie 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 January 2024.

How much traffic does ST 1 a over HWY M Coughlin & Relie carry?

About 102,900 vehicles per day (2024 count), of which roughly 7% are trucks.

How long is ST 1 a over HWY M Coughlin & Relie?

The structure is 169 ft (51.5 m) long with a longest span of 85 ft (25.9 m) and a deck 115 ft wide.

Who owns ST 1 a over HWY M Coughlin & Relie?

It is owned by the State Highway Agency.