The crash happened just over the Illinois-Indiana border east of Lansing, Ill.
Ten-year-old Zanyiah Reese of Gary, Indiana, was a passenger in the car. She was flown by medical helicopter to the University of Chicago Hospital and is in critical condition. Her mother suffered minor injuries.
Investigators say the car went off the expressway, struck the concrete barrier, came back into traffic and got wedged under the semi.
At 7 a.m., the right lane remained closed, Dillahunty said. All lanes later reopened.
The STNG Wire contributed to this report.