US Bridges

I 93 over Water Mystic River

Fair

Middlesex County, Massachusetts · .8 KM S of JCT I93&SR60 · Structure no. M120363B4DOTNBI

Built
1963
62 years old, rebuilt 2011
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
258 ft
3 main spans
Daily traffic
250,350
2019 count
Owner
State
State Highway Agency

About this bridge

I 93 over Water Mystic River is a steel stringer/multi-beam or girder carrying I 93 over Water Mystic River in Middlesex County, Massachusetts. It was built in 1963 and reconstructed in 2011, so it is 62 years old, younger 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 6 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 250,350 vehicles a day, roughly 6% of them trucks, projected to reach 275,206 by 2032. The structure is 258 ft (78.6 m) long and 139 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesI 93
CrossesWater Mystic River
Location.8 KM S of JCT I93&SR60
RouteInterstate 93
CountyMiddlesex County
StateMassachusetts
Coordinates42.41476, -71.10389
Functional classUrban Principal Arterial - Interstate

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53.6 US tons
Inventory rating42.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, precast panels
Main spans3
Design loadHL 93
Structure length258 ft (78.6 m)
Longest span85 ft (25.9 m)
Deck width139 ft (42.5 m)
Roadway width131 ft (39.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic250,350 (2019)
Projected traffic275,206 by 2032
Trucks6%
Lanes on structure8
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$6.5 million (2025 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was I 93 over Water Mystic River built?

It was built in 1963, making it 62 years old in 2025. It was reconstructed in 2011.

What condition is I 93 over Water Mystic River 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 December 2023.

How much traffic does I 93 over Water Mystic River carry?

About 250,350 vehicles per day (2019 count), of which roughly 6% are trucks.

How long is I 93 over Water Mystic River?

The structure is 258 ft (78.6 m) long with a longest span of 85 ft (25.9 m) and a deck 139 ft wide.

Who owns I 93 over Water Mystic River?

It is owned by the State Highway Agency.