While the driver caused the accident after failing to adhere to warning signs to slow down, the board said that Morgan, 46, and other passengers' failure to wear seatbelts and adjust headrests played a role in the severity of their injuries – noting that most injuries were a result of passengers being whipped around or hitting the sides of the limousine-van.
The board also came to the conclusion that if the driver had slowed to 45 mph he would have been able to stop before impact, avoiding the crash.
"One tragic aspect of roadway death is that so often they could have been prevented," Chris Hart, chairman of the safety board, said.
According to AP, the Wal-Mart driver, Kevin Roper, worked for the company for 15 weeks and had nine "critical event reports." The reports, which are produced by the truck's computers and recorded by the company, keep track of hard braking, activation of the vehicle's stability control system and other instances that point to unsafe driving.
Tracy Morgan Settles Lawsuit With Wal-Mart Over Car Crash
Roper's attorney, David Glassman denied that his client had gone without sleep for 28 hours. "Not only are we disputing it, it is factually wrong," he told AP.
Roper was consequently charged with death by auto and four counts of assault by auto after the accident that left James "Jimmy Mack" McNair, a mentor of Morgan's, dead and severely injured four other passengers.
Among the injured was Morgan, who was left in critical condition with a broken leg and was in a coma for two weeks.
Since leaving the hospital, the former 30 Rock star has made a slow but sure recovery.
As recently as last month he was seen during a family trip to Disneyland for his daughter's birthday and was seen again in mid-July walking without a cane or assistance for the first time since the accident.
Morgan continues to make small milestones in his recovery and credits his fiancée and daughter for motivating him to get better.
"I'm happy to be alive," Morgan told PEOPLE in June. "I have my good and bad days…I just want to get better and become healthy. I want to walk my wife down the aisle. I am determined to play with my daughter and chase her around." "All of those things [are] what keeps me going."