ISP said the crash happened on I-80 westbound between La Grange Road and Harlem Avenue in Tinley Park just before 4:30 a.m.
Police said an SUV was driving west when it collided with a semi. The two men killed had been friends since grade school, their families said.
They were identified as Tyler Koscinski, who had just turned 20, and his friend Mason Santiago.
"Oh god, he's just the light. The light of our life," said Koscinski's mother Kelly. "He's a phenomenal brother, athlete and just a goofy, fun kid that loved everyone."
Koscinski loved baseball and even played a year in college at Aurora University to figure out his next move in life.
"He was looking to maybe being a PE teacher. And then being a coach," said father Chris Koscinski. "He just didn't make it there, that's all. "
The pair were on their way home from St. Xavier University, where Santiago went to school and was on the football team, when they were killed.
"They were best friends," Kelly Koscinski said through tears.
Family said Santiago and Koscinski met in third grade and, ever after, did everything together.
"They were goofballs together. They had fun together and danced and competitive sports against each other," Kelly said. "He was, he was like another one of our own here."
ABC7 reached out to the Santiago family, who said their son lived with great passion and love for everyone, and that they sympathize with the Koscinskis in their shared loss.