The crash happened around 4:20 a.m. on I-294 near the Hinsdale Oasis ramp, according to Illinois State Police.
A disabled car was on the left lanes of the Tri-State. ISP said a person from that car stepped out and was struck by a semi.
The person died at the scene.
Toll cameras showed as law enforcement closed two southbound lanes and the ramp to the Hinsdale Oasis around 5:19 a.m.
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No additional information was made available.