You can also see the impression the steel bar made on the car roof.

Park.Premium reports what happened on I-93 southbound just before the Neponset exit in Dorchester around 1:40 p.m. on Tuesday:

A steel bar flew off a black dump truck on I-93 Southbound near Dorchester and shattered my windshield while I was driving. 

Police report filed, of course. But no time to get the plate number, so:

If anyone was driving in the area and has dashcam footage, or recognizes the truck/company, please DM me. This was an extremely dangerous situation ad I’m trying to identify the truck before someone else gets hurt.