conveyors and methods for operating conveyors to accelerate laterally adjacent conveyed articles over different distances . the conveyors provide a conveying surface atop rollers in a conveyor belt . the belt rollers ride on a bearing surface underlying the belt on a carryway . as the belt advances , the rollers riding on the bearing surface rotate in a direction of rotation to accelerate conveyed articles along the belt in the direction of rotation . the bearing surface is shaped so that its length in the direction of belt travel varies across the width of the conveyor .