Massachusetts state police said debris was reported in the middle of Route 128 near exit 26 in Waltham Monday morning.
Police said drivers reported large pieces of rock were reportedly on the northbound side of the highway.
Police said traffic was backed up in the area for a time. Video from SkyFox showed traffic moving along just before 11 a.m.
MassDOT crews were on their way to the area to clean the debris.