Two filing cabinets in the roadway Saturday night were to blame for two separate crashes on Interstate 55 northbound.
Illinois State Police Master Sgt. Fred Rivera said the two vehicles, a van and a passenger car, both swerved to avoid the cabinets in the road.
"One vehicle swerved and ended up in the ditch," he said. "The second unit rolled over."
The crash happened at mile marker 251, which is near the Interstate 55 and Interstate 80 interchange. The crash was at about 8:40 p.m.
Four adults were taken to Provena Saint Joseph Medical Center with non-life threatening injuries.
No tickets were issued in the crash. State police had been alerted to the debris in the roadway and were on their way to the scene, but the crashes happened before they got there.
Rivera said state police do not know why there were two cabinets in the roadway.
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