I 93

over ST 28 & ST38 & TEMPLE ST

3.2 KM N OF JCT I-93&US-1, Middlesex County, Massachusetts

Condition

Fair

Year Built

1973

Daily Traffic

143,941

Length

235 ft

About This Bridge

I 93 carries traffic over ST 28 & ST38 & TEMPLE ST in Middlesex County, Massachusetts. Built in 1973, this structure is 53 years old, placing it among the older bridges still in active service. The bridge features steel continuous construction with a stringer/multi-beam or girder design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 143,941 vehicles cross this bridge daily, making it a high-traffic corridor critical to regional transportation. Bridges carrying this volume require enhanced inspection schedules and proactive maintenance programs. Commercial trucks account for 12% of all crossings. This proportion of commercial traffic is typical for this roadway classification and is factored into the bridge's design load ratings.

The bridge is currently rated in fair condition based on federal inspection criteria established by the Federal Highway Administration. The structure meets current safety standards for its designated use and load capacity. With a total length of 235 feet, this structure falls within the typical range requiring standard inspection procedures conducted by certified bridge inspectors.

The construction materials used in this bridge were selected based on engineering requirements, cost considerations, and local conditions at the time of construction.

Federal law requires that all highway bridges be inspected at least every 24 months by qualified inspectors following the National Bridge Inspection Standards (NBIS). Some bridges with known issues or unusual characteristics may be inspected more frequently. Inspection data is reported to the National Bridge Inventory, a database maintained by the Federal Highway Administration that tracks the condition of all public highway bridges in the United States. This bridge data is sourced from that federal database and reflects the most recent available inspection results.

Condition Ratings

5

Deck Condition

Fair

5

Superstructure

Fair

5

Substructure

Fair

Channel & Protection

N/A

5

Lowest Rating

Determines condition category

NBI condition ratings range from 0 (failed) to 9 (excellent). Ratings of 4 or below are considered poor. The overall condition category is determined by the lowest individual component rating.

The fair condition rating of 5 indicates some deterioration that warrants monitoring but doesn't affect structural integrity.

For a structure built in 1973, this condition level is expected given the bridge's age and usage patterns. High traffic volumes on a bridge in fair or poor condition typically elevate its priority for rehabilitation or replacement in state transportation planning.

Bridge Details

Steel Continuous is the primary structural material, which influences maintenance requirements and expected lifespan. The stringer/multi-beam or girder design was selected based on span requirements, load capacity needs, and site conditions at the time of construction. Maintenance responsibility falls to State Highway Agency.

Construction

Year Built1973
MaterialSteel Continuous
Design TypeStringer/Multi-beam or Girder
OwnerState Highway Agency

Dimensions

Total Length235 ft (71.7 m)
Max Span11 ft (3.3 m)
Deck Width14 ft
Deck Area30,397 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 30,397 sq ft determines surface maintenance scope.

Classification

Route TypeInterstate
Route Number93
Lanes On Bridge8
Lanes Under Bridge11

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour CriticalN
Detour Length1 mi (2 km)

Traffic Data

Traffic volume data helps engineers assess bridge wear patterns and plan maintenance schedules. Average Daily Traffic (ADT) counts are updated periodically and represent typical weekday usage.

143,941

Avg Daily Traffic (2021)

Vehicles per day crossing this bridge

12%

Truck Traffic

Commercial vehicle percentage

228,998

Projected Future ADT

Estimated future demand

This bridge carries approximately 143,941 vehicles per day, translating to roughly 52,538,465 crossings annually. This high volume places significant demands on the structure and necessitates frequent inspections.

Commercial trucks comprise 12% of traffic. Heavy vehicles cause disproportionate wear—a single fully loaded truck can have the impact of thousands of passenger cars on bridge deck surfaces.

Traffic projections estimate future volumes of 228,998 vehicles daily, a 59% increase from current levels. These projections inform capacity planning and potential upgrade requirements.

Load Ratings

Load ratings determine what weight this bridge can safely support. These values are critical for routing heavy vehicles and issuing overweight permits.

Operating Rating

Maximum allowable load for special permits

Inventory Rating

Load level for normal traffic

5-Year Condition Trend

Stable

Condition has remained relatively stable since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

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43.420833, -71.333333

Identification

Structure NumberS170313BHDOTNBI
NBI IDMA-S170313BHDOTNBI
State FIPS25
County FIPS017

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Data Source: Federal Highway Administration (FHWA) National Bridge Inventory 2024

Bridge inspection data is typically updated every 24 months. Conditions may have changed since the last inspection.

“Structurally deficient” does not mean a bridge is unsafe or likely to collapse. It indicates that one or more key structural elements are in poor or worse condition. Bridges are inspected regularly and may have load restrictions in place.

This data is for informational purposes only and should not be used for route clearance or vehicle weight decisions.

I 93 over ST 28 & ST38 & TEMPLE ST | Massachusetts