State police said an over height tractor-trailer set off an alarm before striking two overhead signs in the O'Neill Tunnel on Interstate 93 Tuesday morning.
The first overhead lane use signal was struck on the northbound side of the interstate near the entrance to the tunnel. The second was hit near the Storrow Drive exit.
Some lanes of the tunnel were closed for a time, but were reopened at about 11 a.m.
Just before 11 a.m. the MassDOT Twitter account reported that traffic was backed up to the Braintree Split of Interstate 93. State police said traffic was slightly impacted.
Police said they were reviewing security camera footage in the tunnel to identify the truck that struck the signs.
