The IDOT warning was first issued Wednesday afternoon after pavement buckled on the Kennedy Expressway (I-90/I-94)at Adams.
IDOT had closed all ramps from the eastbound Eisenhower (I-290) to the northbound Kennedy and ramps from westbound Congress to the northbound Kennedy while they work.
IDOT has taken the Kennedy down to one lane going northbound.
Officials said motorists should watch for signs leading to re-routes and traffic advice. They are urging drivers to take the Tollway and Ogden Ave. as alternates. Officials also suggest taking public transportation.
On Wednesday night, the city had experienced ten hours of traffic troubles and counting. Thursday's commute is expected to improve.
"We've been working nonstop around the clock and will continue to do that throughout the night. We are very hopeful to have all lanes open by the morning rush. There are no guarantees but we are very hopeful and we're on the right track to do that," said Marisa Kollias, Illinois Department of Transportation.
On Wednesday night, crews were busy laying quick-drying cement.
IDOT reports that workers with Lorig Construction were filling an underground freight tunnel with concrete when the road buckled just before noon. And that means the outbound Kennedy Expressway has been down to one lane all day and night, taking drivers three times as long to get to their destination.
"It usually takes 10 minutes. Now it's like half an hour. You have to come off a detour, get back on. But it's something like typical for Chicago," said Edward Culbreath, driver.
"Horrible," said Amal Jada, driver.
"It's just an inconvenience but that's city living for you, that the unexpected can happen," said Perry Fryer, driver.
Lorig Construction is a family-owned business based in Des Plaines. The company's Web site says its been involved in almost every major reconstruction project in Chicagoland, projects ranging from $10,000 to $70 million.
IDOT says it will take time to figure out what happened and who's responsible.
"It could take days. Could take a few weeks. We're assessing the situation and doing the best we can to figure out what happened at quickly as possible," said Kollias.
In the meantime, several on-ramps to the Kennedy remain closed, impacting thousands of drivers on Wednesday night and into Thursday and each one has a different approach to the problem.
"I don't think I want to be on the road with the other people who might not be quite as patient. Not tonight," said Megan Kossuth, driver.
"I haven't been calm. I'm very frustrated," said Katina Pearson, driver.