The truck driver who police said was dozing prior to crashing into a limo bus carrying Tracy Morgan and friends, killing at least one person, has been charged. The 18-wheeler driver, Kevin Roper, 35, turned himself in last night according to TMZ; he has been charged with one count of death by auto and four counts of assault by auto.

"[The] driver failed to observe slow-moving traffic ahead," New Jersey State Police Sgt. First Class Gregory Williams said on Saturday. "He observed at the last minute—just prior to impact—the limo bus carrying Morgan and his party."

Morgan, fellow comics James “Uncle Jimmy Mack” McNair, Ardie Fuqua and Harris Stanton, and manager Jeffrey Millea were all in the limo bus on the New Jersey Turnpike on their way back to NYC after a comedy show in Delaware around 1 a.m. Saturday morning when the crash occurred. McNair was killed and at least two others were injured in the crash.

Police said that when Roper saw the limo bus in front of him, he swerved left to avoid it, but struck it in the rear anyway, then hit another vehicle. The limo bus driver lost control, began rotating clockwise, and then turned over onto its left side, hitting three other cars in the process.

Limo driver Tyrone Gale told ABC that he heard Morgan screaming after the crash: "I climbed around and heard Tracy screaming for help," he said. "I climbed up on the body of the limo bus ... but I couldn't reach them." He said there was a lot of confusion in the immediate aftermath: "I just remember the impact...We didn't know which way was up, which way was down. I don't know if we flipped several times or one time," said Gale. "I saw the condition of everybody and I knew it would just make it worse if I tried to pull them up and out of the vehicle."

Gale also wrote on Facebook:

Thank you everyone for all the support and love, I truly am blessed to have you as well. My day was truly amazing with the great Tracy Morgan James Mcnair Ardie Fuqua Harris Stanton Jeff Millea. The fans at Dover Downs can testify to the amazing show they witnessed. I can only say feeling helpless on the highway was very hard to take. There was nothing I could do but scream at times. I am truly sad for the loss of James Mcnair. This is not something I will be able to forget in my lifetime. I wont pretend like I knew them deeply, but I will say I truly know when i'm around good people and these men are. RIP James Mcnair. Love FB hugging my family closer.

Morgan's ex-wife told the News that he has a broken leg and is still unconscious, but doctors expect him to recover. She added that the couple's three children are "not holding up well at all."

The National Transportation Safety Board told the AP it was working with state police to look at any issues in the crash related to commercial trucking and limousine safety. Roper had been driving a Wal-Mart 18-wheeler; Wal-Mart president and CEO Bill Simon said in a statement: "This is a tragedy and we are profoundly sorry that one of our trucks was involved...The facts are continuing to unfold. If it's determined that our truck caused the accident, Walmart will take full responsibility."