Comedian Tracy Morgan underwent surgery yesterday for his broken leg, one of the many injuries he suffered when a tractor trailer apparently struck the limousine he and other comedians were traveling in on Saturday. His representative Lewis Kay said, "While Tracy remains in critical condition, he has been more responsive today, which is an incredibly encouraging sign." Update: The criminal complaint has new details about the truck driver's condition—as in how he hadn't slept for a day.

Kay added, "He sustained a number of injuries including a broken leg, a broken femur, a broken nose and several broken ribs. He had surgery earlier today on his leg. We expect him to remain in the hospital for several weeks. His family is tremendously overwhelmed and appreciative of the outpouring of love and support from his fans."

Morgan and fellow comics James “Uncle Jimmy Mack” McNair, Ardie Fuqua and Harris Stanton, plus manager Jeffrey Millea were all in a Mercedes Sprinter limo bus on the New Jersey Turnpike, headed back to New York after a comedy show in Delaware, when the driver of a Walmart 18-wheeler rear-ended their vehicle at 1 a.m. on Saturday morning. Police believe that the truck driver, Kevin Roper, was dozing and "failed to notice slow-moving traffic" ahead. When Roper tried to avoid the limo bus, police say he swerved left to avoid it, but struck it in the rear anyway, then hit another vehicle.

The limo bus driver, Tyrone Gale, lost control, began rotating clockwise, and then turned over onto its left side, hitting three other cars in the process. Gale later said, "I climbed around and heard Tracy screaming for help. 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. 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."

McNair was killed, while Morgan, Millea and Fuqua remain in critical condition at Robert Wood Johnson University Hospital in News Brunswick, NJ. Roper was charged with one count of death by auto and four counts of assault by auto.

The National Transportation Safety Board will be investigating the crash. According to the Star-Ledger, "The spokesman, Keith Holloway, said the NTSB sent a team of investigators because the Saturday morning crash involved multiple commercial vehicles, a tractor trailer and a limousine, and could provide safety lessons for the future... 'If we can take that information and can use it to prevent accidents like this from happening, that will help us achieve our goal,' Holloway said."

Walmart has stated that if it's determined their vehicle caused the accident, they will take "full responsibility."

Update: The Star-Ledger reports, "The complaint charges that Kevin J. Roper, 35, of Georgia, was driving his tractor-trailer on the N.J. Turnpike in Cranbury early Saturday morning, ' without having slept for a period in excess of 24 hours' before he struck the 2012 Mercedes van carrying Morgan."