(WSB Radio)  Drivers in west Cobb County remain on high alert, on the lookout for whomever has been throwing rocks at cars.

27 vehicles have been targets so far.  It's been happening at Dallas Highway and John Ward Road, so police have stepped up patrols in that area.

To date there have been no injuries, but police credit luck for that. 

"It's extremely frightening," says one woman who was driving her son home from scouts when their car was hit.  "Because, at first, you hear this loud bang and you don't know what it was.  And then I saw the windshield just start to crumble and my son started to cry."

She's very aware just how dangerous the situation is.

"Whatever it was, if it had come through, it could have killed either one of us."