Inbound lanes of the Dan Ryan Expressway were closed for three hours during the Friday morning rush after a man was shot near 69th Street.
Troopers responded around 5:20 a.m. and found the shooting victim, Illinois State Police said.
Paramedics took the man to the University of Chicago Medical Center with gunshot wounds to his legs, Chicago Fire Department spokesman Larry Langford said. He was listed in serious-to-critical condition, he said.
Inbound lanes were closed at 71st Street until they were reopened shortly before 8:45 a.m., state police said.
No other information was immediately available.
State police asked anyone who witnessed the shooting or has any knowledge of the incident to contact officials by phone at 847-294-4400. Witnesses can remain anonymous.