Something similar happened to my bro's gf. A portion of a trucks leaf spring roughly 18" long got kicked up and broke through her windshield and landed in the passengers seat. That day we all came in from different directios so we all drove. Had the whole family been riding together... she woulda been gutted by the debris. Damage: broken windsheild, and ripped up seat/backrest.

CHP didn't let us drive her car home. They also told us that type of accident happens regularly with not so good outcomes.

Glad you were lucky.