Updated

The driver of a bus that crashed in Virginia, killing four passengers, has been ordered to serve six years in prison

Prosecutor Tony Spencer says Kin Yiu Cheung was sentenced Wednesday in Bowling Green to 40 years with 34 years of his sentence suspended.

The 38-year-old driver was convicted last November of four counts of involuntary manslaughter in the May 2011 crash on Interstate 95.

The bus was en route from North Carolina to New York when it crashed about 30 miles north of Richmond. Witnesses described Cheung's driving as erratic before the bus swerved off the interstate, hit an embankment and overturned.

A state trooper had testified at trial that Cheung nodded when asked whether he'd fallen asleep behind the wheel. Cheung's attorneys have called it a "horrendous accident."