That's when they say he ran off the road, overcorrected, ran off the road a second time, hit a ditch, then a tree, and was partially ejected.
Investigators estimate Kozlowski was driving 70 miles per hour in a 45 mile per hour zone at the time, and they say he was not wearing a seat belt.
No one else was in the truck, and no other vehicles were involved.
At this point, alcohol does not appear to be a factor in the crash.
Kozlowski was a senior at Clayton High School.
As word of his death spread, friends were eager to share their greatest memories of Kozlowski.
Some posted them to a Facebook memorial page, and also shared their memories with Eyewitness News.
One friend recalls the day of a dance competition, when she was especially nervous.
He let me sign my name on his truck," said Erin-Elizabeth Nesmith. "It said, 'I love you big bro,' and he wrote next to it, 'I love you too li'l sis,' and I'll never forget that."
Others say they will remember his selflessness and humor.
"He was the type of person that putall others before himself," said Katie Lynch and Chelsea Taylor. "His dancing skills or lack of always made everyone laugh. He was the best guy around and the saying is right, only the very best die young."
Kozlowski's best friend, Phillip Worrell, will also carry with him fond memories - in addition to the memory of seeing Kyle in his last moments.
Every single time we get on Loop Road and he was behind me in his truck, he would pass me," Worrell said. "He was going way too fast and last I saw of him he was going around the curve before you get to where the accident happened. And that was the last I saw of him."
Grief counselors will be at Clayton High School Tuesday to help students cope with the loss of their classmate.
A memorial service will be held for Kozlowski on Thursday at 4 p.m. at the Clayton Center.