The crash occurred in the outbound lanes near Damen Avenue at about 1:55 a.m, Illinois State Police said.
Police said a motorcycle is believed to have stopped in the middle lane and the driver got off when a sedan struck the motorcycle and the driver.
The motorcycle driver was transported to a hospital, where he died, police said.
He was identified as Adduin J. Gonzalez, 26, the medical examiner said.
The driver of the sedan remained on the scene.
The outbound lanes of I-55 were closed as police investigated before reopening shortly before 6 a.m.
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