The truck driver who left Tracy Morgan in a critical condition hadn't slept in more than 24 hours.

The '30 Rock' star sustained a number of serious injuries after the limo he was travelling in overturned when a Walmart truck driven by Kevin Roper ploughed into it, causing a seven-car pile up on the New Jersey Turnpike and killing comedian James ''Jimmy Mack'' McNair on Saturday (07.06.14).

A criminal complaint filed today (09.06.14) against Roper, obtained by E! News, states the 35-year-old truck driver caused the accident by driving his truck ''without having slept for a period in excess of 24 hours.''

The driver, who has been charged with one count of death by auto and four counts of assault by auto, but is currently free on $50,000 bail, is expected to appear in a New Jersey courtroom today.

Former 'Saturday Night Live' comedian Tracy, 45, sustained multiple injuries in the crash, including a broken leg, a broken femur, a broken nose and several broken ribs.

A spokesperson for the actor, whose family are by his side at Robert Wood Johnson Hospital in New Brunswick, previously said: ''We expect him to remain in the hospital for several weeks.''

The actor's friend and travelling partner Ardie Fuqua was also airlifted to the hospital.