Thick glass penetration

[afss]

Few days ago, there was an incident where an escavator's operator used his machine to conduct a terrorist attack. He ran over a pedestrian and killed him and then he overturn a bus, luckily without passengers.[/size]A policeman and two wardens who passed by, shot him and killed him and by thus stopped him from continue the rampage.From my knowledge, the glasses of such machines is thick and hardend, as it design to protect the operator from falling stones etc.Does any of you have knowledge about penetration tests, conducted with various types of ammunition, to show which on is more efficient?If so, could you send a link or the whole report?Thank you