FALMOUTH — New cable guardrails installed along Interstate 295 north of Portland may have prevented a major accident today when they stopped a careening tractor-trailer from crossing into the median.

State Police say the tractor-trailer was headed southbound at 2:04 p.m. when it appears to have blown a tire, causing it to swerve toward the median. The cable guardrails, which were installed this summer, are designed to absorb the impact of a vehicle without breaking or forcing it back into traffic.

Trooper Marvin Hinkley said the cables caught the truck and prevented it from going into the northbound lanes of oncoming traffic. Hinkley said a truck crossing into the oncoming lanes would have been “catastrophic.”

Traffic lanes remained open though passing lanes will be temporarily shut down when the truck is removed, Hinkley said.

The truck is owned by Sam’s Transportation of Georgetown, Mass., and was driven by Michael Willett of Newton, N.H.