I thought we weren't allowed going over 4 hours? Or special provisions must be made to the pax? I honestly don't know the rule off the top of my head.

I recently sat as number 4 on twy D in ORD to depart for 3:50. Pretty much everyone returned to the gate after about 3:30. All claiming that their companies' rules stated 3-4 hours was the limit due to pax rights.