This project sheet combines two adjacent highway-widening projects in Greater Boston. The projects widened almost nine miles of highway and rebuilt seven permanent bridges, including two over navigable waterways. All work needed to confirm to strict lane closure schedules.

Additional scope included:

• MSE and cast-in-place retaining walls.
• 50,000 LF of new permanent highway barrier.
• Two miles of noise barriers.
• Extension of two active culverts carrying the Blue Hill River under the Interstate.
• Recreated and remediated wetlands including in areas inhabited by endangered species.
• New drainage, lighting, water, sewer and gas lines.
• Two temporary interstate bridges to accommodate highway lane shifts.