WASHINGTON — The National Transportation Safety Board is scheduled to meet Tuesday to determine the cause of an accident last year that severely injured comedian Tracy Morgan and killed another comedian after a truck smashed into their limousine during a traffic backup on the New Jersey Turnpike.

The safety board is also expected to make safety recommendations based on the accident.

Much is already known about the crash. Accident investigators have previously said Wal-Mart truck driver Kevin Roper was going 65 mph in a highway work zone where the speed limit had been lowered from 55 to 45 mph, despite two warning signs alerting approaching motorists to slow down.

The chauffeured limo van in which Morgan and other comedians and friends were riding was pushed into slow-moving traffic ahead. A total of six vehicles were involved in the June 7, 2014 crash.

Comedian James “Jimmy Mack” McNair of Peekskill, N.Y., a mentor of Morgan’s, was killed. Morgan suffered head trauma, a broken leg and broken ribs. Three other passengers in the limo suffered serious injuries.

Morgan, a former “Saturday Night Live” and “30 Rock” star, and the others were returning from a show in Dover, Delaware.

Roper was charged with death by auto and four counts of assault by auto in state court in New Jersey. The criminal complaint alleged Roper operated the truck “without having slept for a period in excess of 24 hours resulting in a motor vehicle accident.” A person can be charged with assault by auto if he or she causes injury after knowingly operating a vehicle after being awake for more than 24 hours under New Jersey law.

The safety board has long raised concerns about operator fatigue leading to accidents across all modes of transportation, from airline pilots to train engineers.

In May, Morgan and two friends injured in the crash settled a lawsuit against Wal-Mart for an undisclosed amount. The Bentonville, Arkansas-based company settled a wrongful death claim filed by McNair’s children for $10 million, according to court papers.

Using a cane, Morgan made his first public appearance this June on NBC’s “Today” show and said he hoped to resume his career but that he wasn’t 100 percent healed. He hasn’t performed since the accident.