The truck driver charged in the fatal highway crash last weekend that injured comedian Tracy Morgan and several other people has pleaded not guilty at an initial court appearance.

Kevin Roper appeared in state court in New Brunswick, N.J. on Wednesday to face death by auto and assault by auto charges. A judge kept his bail at $50,000 US. Roper and his attorney, David Glassman, declined to speak with reporters after the brief hearing.

Roper was driving a Wal-Mart truck early Saturday morning when he allegedly swerved to avoid slowed traffic on the New Jersey Turnpike and plowed into Morgan's limo.

A criminal complaint alleges the 35-year-old Roper, of Jonesboro, Georgia, hadn't slept for more than 24 hours before the accident. Wal-Mart has said it believes he was in compliance with federal safety regulations.

A conviction on a death by auto charge carries a five-to-10-year prison sentence. Each assault by auto charge is punishable by up to 18 months in prison.

Tracy Morgan Accident

Truck driver Kevin Roper, seen in an image released by New Jersey State Police, is set to appear in court Wednesday. (New Jersey State Police/Associated Press)

The 45-year-old Morgan suffered a broken femur, a broken nose and several broken ribs. His friend and fellow comedian James "Jimmy Mack" McNair was killed, and two other passengers were seriously injured. Another passenger was treated and released from the hospital Saturday, and the limo driver and one more passenger were not injured.

Morgan underwent surgery for his broken leg and remained in critical but stable condition Tuesday at Robert Wood Johnson University Hospital.

911 recordings released

State police on Tuesday released audio recordings from three calls to the emergency dispatcher made after the weekend accident.

"It's a terrible accident," a woman tells the dispatcher in one of the calls. "The car flipped. It's on its side. It's two vehicles and a Wal-Mart truck."

Citing the criminal investigation, a Wal-Mart spokeswoman wouldn't say Tuesday where Roper's trip had originated or where he was headed at the time of the crash. Roper's New Jersey-based attorney didn't return messages seeking comment Tuesday.

FX Networks issued a statement Tuesday saying Morgan's new series, a half-hour comedy scheduled to start filming in August for a January premiere on the FXX network, would be waiting for him once he's well.

Meanwhile, accident investigators are looking into what role Roper's commute might have played. NTSB spokeswoman Kelly Nantel said that though he lived in Georgia, his job was based in Delaware. Wal-Mart has not explained what Roper's driving route was.