Case Study: Boston Central Artery/Tunnel Project Design Revisions Delay Construction (2001)

Project Overview
• Name: Boston Central Artery/Tunnel Project (“Big Dig”)
• Location: Boston, Massachusetts
• Year: 2001
• Project Size: Over $14 billion (total project)
• Scope: Construction of underground highway tunnels and associated infrastructure
• Lead Agencies/Contractors: Massachusetts Turnpike Authority /

Category of the Issue, Problem, or Challenge
• Design
• Structural & Systems Integration

Summary of the Issue, Problem, or Challenge
Complexity of integrating highway tunnels with existing infrastructure led to multiple design revisions during construction. Structural design adjustments were needed to address unforeseen subsurface conditions and mechanical system conflicts, causing significant schedule impacts.

Root Cause Analysis

• Incomplete subsurface utility and geological data at design time.
• Poor integration of mechanical, electrical, and structural designs.
• Fragmented contract management across multiple contractors and design teams.
• Reactive design approach responding to field issues rather than proactive planning.

Impacts Due to the Issue, Problem, or Challenge
• Multi-year delays with cost overruns exceeding $2 billion.
• Increased public scrutiny and regulatory intervention.
• Safety incidents linked to rushed or altered design implementations.

Corrective Actions Taken

1. Increased geotechnical and utility investigations to improve design accuracy.
2. Established integrated project delivery frameworks to align design and construction teams.
3. Enhanced use of coordinated 3D modeling and systems integration platforms.
4. Strengthened project management oversight with clear accountability.

Lessons Learned

• Large complex projects require extensive upfront site data and integrated design.
• Fragmented management leads to coordination failures and costly rework.
• Proactive design integration with mechanical/electrical systems is essential.
• Strong project management and communication frameworks reduce risk.

Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation

• Has comprehensive subsurface and utility data been collected and integrated?
• Are mechanical, electrical, and structural designs fully coordinated?
• Is project management structured to ensure accountability and integration?
• Are integrated design and delivery methods being used effectively?