A Cohasset man has been cleared of charges that he caused the death of a 74-year-old Rhode Island man in a traffic crash on Interstate 95 south. Michael Casey was acquitted at a bench trial Wednesday of motor vehicle homicide by negligent operation. Prosecutors said the 27-year-old Casey fell asleep and crashed into a guard rail while on his way to work at about 5:30 a.m. Oct. 5, 2010. Casey could not move his vehicle so he got out and left it in the highway’s right travel lane to call police. Wilfred Gibault of Providence died when he struck Casey’s vehicle from behind.