Boston I-93 HOV Lane Case Study

A smart, safe, and long-term solution for congestion management.

The Massachusetts Department of Transportation (MassDOT) needed a way to manage growing congestion along one of the busiest corridors in the Boston area—the I-93 Southeast Expressway. What began as a temporary fix turned into a 20+ year success story thanks to the flexibility, reliability, and safety of the Road Zipper System™.

Instead of spending up to $1.2 billion on a full freeway widening project, MassDOT implemented a moveable barrier system to create a contraflow high-occupancy vehicle (HOV) lane—adding capacity during peak travel times without permanent construction.

Moving People. Safer. Faster. Smarter.

Key Results

Up to 8,200 vehicles/day using the managed lane system
6-mile stretch of I-93 with positive barrier separation
20+ years in operation—twice the intended lifespan
Operational every weekday:
- AM Peak: 5:00 a.m. – 10:00 a.m.
- PM Peak: 3:00 p.m. – 8:00 p.m.
Eliminated risk of head-on collisions with continuous, moveable barriers
Enhanced incident response with dedicated management areas and staged tow trucks

Why The Road Zipper System?

The Road Zipper uses a patented machine and interlocking barrier design to create flexible, reversible lanes. In Boston, it enabled the creation of a safe and efficient HOV lane within the existing road footprint—no new lanes, no full reconstruction, and no disruption to the general-purpose lanes.

Barriers can be moved up to 24 feet in one pass
Transfer speed up to 10 mph
Designed for tight curves and expansion joints
Operates daily with minimal disruption

customer testimonial

“Operational safety was one of the greatest concerns expressed when the project was proposed. Two decades later, we have a proven track record of just how safe this technology is.”

Chuck Fuhs

I-93 HOV Consultant

Parsons Brinckerhoff

Built on reliability and maintenance.

One of the biggest factors in the I-93 system’s longevity is the exceptional maintenance performed by the MassDOT HOV Operations team. With routine care and attention, the two original barrier transfer machines operated successfully for two decades—well beyond their planned lifespan.

Defying expectations, delivering results.

What began as a temporary solution became a long-term win for Boston commuters and taxpayers. The Road Zipper System delivered unmatched value, improving safety and traffic flow while avoiding massive infrastructure costs. Now, instead of rebuilding, MassDOT is reinvesting in the system—because it works.

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Road Zipper Case Study | Boston I-93 HOV