NEW : NTSB investigators looking for video of bus driver 's casino activities before the accident . Comment: Driver of tractor-trailer disputes bus driver account of crash involvement , police source says . The crash occurred about 5:30 a.m. on a stretch of I-95 called the New England Thruway near the Bronx-Westchester County line , officials said . Witnesses say bus was traveling very fast before accident that killed 15 .
NEW : NTSB investigators looking for video of bus driver 's casino activities before the accident . Comment: Driver of tractor-trailer disputes bus driver account of crash involvement , police source says . Witnesses say bus was traveling very fast before accident that killed 15 .