I've driven through the entire I80 span so many times through the east and west... If you're coming in through Iowa, the first 115 miles are easy rural highways, rarely any police on the road never any traffic.
Once you cross the last rest stop into the i55 junction, it gets haywire from there with constant traffic, constant build up and traffic that plague the area. Once you get past that, it gets built up once 80 and 294 merge together and it could take 40 minutes to go 10 miles over the Indiana border. It's not backed up thankfully late at night.
Entering in from Indiana can take a while but pay attention to your GPS because there's alot of highways crammed in this area. Getting to i80 requires you to get one lane that many people fight through. The rest of the drive is easy from there
Overall the roads are awful! Construction is awfully slow and there's tons of accidents. The rest stops are awful except the one travel plaza. Plus there's not enough rest stops but I still rather take 80 than 88 read more