Driver Ophadell Williams maintains he was in control of the bus until a passing tractor-trailer veered suddenly on Interstate 95, one of the lawyers, Sean H. Rooney, said.
Williams contends he lost control while swerving to avoid a collision with the truck, Rooney said Thursday.
"This is, plain and simple, an accident, a tragic one," Rooney told The New York Times.
In the March 12 accident, the bus overturned and hit a signpost on I-95 in the Bronx on its return to Manhattan's Chinatown from the Mohegan Sun casino in Connecticut.
Federal investigators are attempting to determine the cause of the crash while the State Police are trying to decide if criminal charges are warranted, the Times reported.
Williams provided a sworn statement to the federal investigators last week at the offices of the bus company, World Wide Travel, in Brooklyn, Rooney said.
The police also tested his breath three times for alcohol and found no trace each time, he said.