The car was driving inbound on the Stevenson when Illinois State Police said at about 4 a.m. it lost control near Ashland Avenue and crashing into and over the concrete wall. The car landed on the street below at Archer Avenue and Robinson Street.
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A total of four people were in the car and two people, a 27-year-old man and a 22-year-old woman, were killed, police said. The Chicago Fire Department said a 21-year-old woman and a 25-year-old man were transported to Stroger Hospital in serious condition.
Authorities have not released the identities of the two people who were killed.
It is not known what caused the crash, but police said their preliminary shows the car was traveling at a high rate of speed. Police also confirmed there was a snow bank on I-55 where the car lost control, but it's unclear if it was a factor in the crash.
Police said the car also hit a light tower and knocked out the lights on the Stevenson in both directions between Ashland and the Dan Ryan Expressway.
Safety advocates said the horrific accident is a reminder of the dangers of traveling during winter weather. Drivers should watch their speed, leave plenty of distance between cars, and make sure they don't brake on ice to avoid skidding, sliding and spinouts, experts from AAA said.