Officials said that “non-structural concrete at an expansion joint” below Huntington Avenue became dislodged and fell into a travel lane on the interstate.

Concrete debris fell from the Prudential Tunnel in Boston Friday afternoon, hitting several vehicles. State Police said the debris fell into the left and middle travel lanes in the tunnel on the westbound side of the Mass Pike. All traffic on the westbound side of the Mass Pike is being diverted while the debris is removed.