As design lead for the White-Kiewit Design-Build Team, Tetra Tech provided overall design management, highway design, environmental permitting, and traffic engineering services for the I-93 Superstructure Replacement Project, which is the largest accelerated bridge effort ever undertaken by the Massachusetts Department of Transportation (MassDOT).

Dubbed the “93 Fast 14,” this more than $98 million project involved replacing 14 bridge superstructures along the I-93 corridor, the primary north-south route into Boston, on an extremely expedited schedule.

Using conventional methods, this type of bridge replacement would take at least four years to complete. Our design team helped make it happen in 10 weekends by implementing customer service and safety-driven innovations including design-build procurement, Accelerated Bridge Construction methods and techniques, and creative traffic and contingency management. During bridge demolition and replacement, our team’s design helped minimize construction-related impacts and congestion on I-93 and area roads. This was no easy feat considering the bridges carry around 200,000 vehicles per day.

Per Tetra Tech's detailed traffic management plan, one four-lane barrel of I-93 was closed and two lanes of the closed barrel were redirected into the other barrel each Friday night at 8:00 p.m. The two opposing directions of traffic were separated by a moveable "zipper" barrier installed throughout the 4.5-mile construction zone. All lanes were successfully reopened each Monday by 5:00 a.m. to accommodate the morning rush hour.


The 93 Fast 14 Project is a national model of engineering excellence and innovation, particularly in the burgeoning transportation design-build sector. It has received a string of accolades including:

  • National Honor Award from the American Council of Engineering Companies
  • Francis B. Francois Award for Innovation from the American Association of State Highway and Transportation Officials