Yellow Roadway (YELL) boosted second-quarter guidance for the second time in a month as all units posted a "strong finish."In a press statement after the bell Thursday, the transportation services company announced that it expected to exceed the upper end of its already increased guidance of 85 cents to 90 cents a share. On June 14, Yellow Roadway had raised its second-quarter earnings estimate from 70 cents to 75 cents a share, citing "excellent execution along with favorable economic conditions." Shares of Yellow Roadway were up nearly 4% in after-hours trading after closing at $38.32, down $1.19, or 3%. Yellow Roadway will release second-quarter results July 22.