By Vi Nguyen

CHICAGO (CBS) — A moment Chicago drivers have been waiting for: Some ramps are finally reopening at the Jane Byrne interchange.

This is a big milestone in the major road construction project that’s still way behind schedule.

Drivers have been frustrated with the construction project on the Jane Bryne interchange ever since it started in 2013.

But the state hopes opening these ramps will provide some relief.

An IDOT spokesperson told CBS 2 the plan is to have the ramps open around 8:30 a.m. Saturday, including the Morgan Street exit.

The inbound Dan Ryan ramps to the outbound Eisenhower and inbound Ida B. Wells, as well as the Morgan Street exit, were fully opened at approximately 7:50 a.m.

The state is celebrating a milestone in the project, but it’s nowhere close to being done.

The project was supposed to be done in 2019, but now the state says it won’t be completed until 2022.

So what caused the delay?

The IDOT regional engineer says they didn’t realize how bad conditions were at I-55 and Lake Shore Drive until after they started work on the Jane Byrne interchange project.

The cost of the project was estimated at $475 million. That price tag is now $600 million.

CBS 2’s Tim McNicholas spoke to Anthony Quigley, an IDOT regional engineer, Friday.

“With the impact and the delays and the coordination, we have some costs that go up over the time. With the coordination to do the work at I 55 and Lake Shore Drive. That’s been the big reason for the cost,” Quigley said.

He said it is a very complicated project.

An additional lane between Halsted and Racine will open next week, the project moves into a new phase next spring, where commuters will have to learn a new routine with additional lane changes and closures.