The driver of a school bus that hit and killed a 12-year-old boy in Rockland pleaded guilty in court Tuesday afternoon to a civil violation. Jeffrey Colburn, 65, of Camden was charged with manslaughter in January after Brayden Callahan was run over by Colburn’s bus two months prior and died from his injuries. Colburn initially pleaded not guilty to the manslaughter charge, but as part of his plea deal, admitted to a civil violation for a traffic crash that resulted in a death.