Lanes of I-80 were reopen Saturday morning after an tanker truck flipped over late Friday in the south suburbs.
The tanker was overturned at Harlem Avenue near Tinley Park, Illinois State Police said.
All westbound lanes were closed from about 11 p.m. until 5 a.m. Saturday, police said.
State police said they were inundated Friday night with calls of traffic accidents on Chicago area expressways.
All available state troopers in District 5, where the tanker overturned, were responding to accidents on expressways, police said.
The expressways were partly covered with snow or ice Friday night, according to the Illinois Department of Transportation.
Snow was falling south of I-80 Friday evening, according to the National Weather Service, which warned of hazardous driving conditions.