Springfield, IL here. Just take 55 north to I 294 north. DO NOT take I-39 to I-80. In addition to it adding 20-25minutes (You are heading west then cutting over, wheras I-55 to 294 is almost a straight shot), you have the Abraham Lincoln Bridge near Lasalle-Peru down to only one lane in both directions, plus several other one lane closures up closer to I-80. Most of these are due to overpass rehabs and are .5 to 1 mile in length. I was just through this area on May 30th.
I-55 to 294 is only 2.75-3hrs from Bloomington depending on speed. I usually go 75mph all the way. Of course once you hit the Tri-State international raceway you may vary your speed up to 80-85 just to stay with traffic. The last few times that I have been through the Chicago area 294 tollway traffic had been lighter than usual especially during early morning hours.
My old home was 15 miles SW of Springfield and it was 4hrs flat from my front door to the front parking gate at SFGAM using this route.
It's the most fun in the park when your laughing in the dark.