Tracy Morgan remained in critical condition Sunday but appeared to show signs of improvement after a car wreck a day earlier that killed another passenger, the comedian's publicist said.

"He has been more responsive today, which is an incredibly encouraging sign," Lewis Kay said.

Morgan's limo van was hit by a tractor-trailer on the New Jersey Turnpike at about 1 a.m. Saturday, according to Sgt. Gregory Williams of New Jersey State Police.

Morgan suffered several injuries, including broken ribs, a broken nose, a broken leg and a broken femur. He underwent surgery on his leg on Sunday, Kay said, noting any road to recovery would be a long one.

"We expect him to remain in the hospital for several weeks," he said.

The chain-reaction wreck killed Morgan's fellow passenger, comedian James McNair, who performed under the name Jimmy Mack, and injured several others, according to officials.

The truck driver charged in the crash has turned himself in, police said Sunday.

Kevin Roper, 35, posted a $50,000 bail Saturday night, according to James O'Neill, spokesman for the Middlesex, New Jersey, district attorney's office.

Comedians Ardie Fuqua and Harris Stanton were among the injured, as was Jeffrey Millea, Williams said. One person was released Saturday, but Robert Wood Johnson University Hospital in New Jersey wouldn't disclose that person's name.

Two others remained in critical condition Sunday, hospital spokeswoman Zenaida Mendez said.

CNN reached Fuqua's agent on Sunday, but he had no comment.

Walmart employee charged

Roper is charged with one count of death by auto and four counts of assault by auto after the tractor-trailer he was driving crashed into the limo bus, a statement from Middlesex County Prosecutor's Office said.

1. Who is injured?
2. Is he any better?
3. Who said so?
4. How is he better?
5. Who hit him?
6. With what?
7. Where?
8. When?
9. Says who?
10. Of where?
11. What was one thing that was injured?
12. What else?
13. Who did the driver work for?
14. Did anybody die?
15. Who?
16. What was his stage name?
17. Who else was hurt?
18. Who else?
19. What kind of vehicle did he hit?
20. What is the hospital?

Provide a numbered list of answers.
1. Tracy Morgan remained in critical condition
2. Yes
3. His publicist
4. He's more responsive
5. Kevin Roper
6. A tractor-trailer
7. On the New Jersey Turnpike
8. At 1 a.m. Saturday
9. Sgt. Gregory Williams
10. New Jersey State Police
11. Femur
12. ribs
13. Walmart
14. Yes
15. James McNair
16. Jimmy Mack
17. Jeffrey Millea
18. Ardie Fuqua
19. limo van
20. Robert Wood Johnson University Hospital