SUMMIT, Ill. -- 13 cars collided on the Stevenson early Friday morning after a semi truck driver fell asleep on the expressway.
It happened around 3:40 a.m. in the northbound lanes of I-55 south of 1st Avenue near Summit.
Illinois State Police say the truck driver admitted to falling asleep.
There was construction in the area.
Fifteen people were injured, six were taken to the hospital with non-life threatening injuries.
The other nine people refused medical attention.
Six fire departments responded to the crash.
All lanes on I-55 were closed south of 1st Avenue for hours as crews cleaned up the crash.
Lanes reopened by 6:00 a.m.