NEW YORK (AP) — A manslaughter trial set to begin Thursday will determine whether a tour bus driver should be held responsible for the deaths of 15 passengers when the vehicle slammed into a guardrail and crashed last year, shearing the roof end to end.

Ophadell Williams pleaded not guilty to manslaughter and criminally negligent homicide in the March 12, 2011, accident after prosecutors said he was seriously sleep-deprived but drove anyway.