By Beth Germano

BOSTON (CBS) – It was a horrific crash that changed lives forever. Now 20-year-old Nikolas Pappadopoulos is facing trial for negligent driving on the Arborway September 6, 2013 when his car clipped the median and slammed into a pickup truck driven by 34-year-old Kevin Cellucci, who is still in rehabilitation with a traumatic brain injury.

“This individual chose to drive like he was driving on the highway, on the parkway,” said prosecutor Montez Haywood.

Prosecutors claim he was driving at least 20 miles over the speed limit, which the defense disputes.

Also in Pappdopoulos’ car were three school friends who were also injured, including one who is paralyzed from the waist down. He recalled a conversation with Pappadopoulos in which the defendant said he was “sorry”.

Arborway crash on September 6, 2013 (WBZ-TV)

Arborway crash on September 6, 2013 (WBZ-TV)

A friend of Kevin Cellucci who was a passenger in the pickup remembered the impact. “I said to Kevin can you believe what just happened. I looked over and he was unconscious,” said Mark Glynn.

The defense is disputing there was a posted speed limit and says there’s evidence another vehicle may have caused Pappadopoulos to swerve that day, calling the prosecutor’s claims “wild and exaggerated.”

“This was an investigation where they drew conclusions and filled in the gaps later,” said defense attorney John Amabile.

Pappadopoulous was expected to plead guilty to negligent driving in November 2014, but there was a sudden change of plea and a claim of new evidence in the case.

Beth Germano