It depends on what time and where. Anytime you head into the downtown area there is a good chance traffic will slow down. Starting this year, and continuing for the next 2 years the " Circle Interchange" I 90 94 290 , is being rebuilt. That is THE major interchange for Chicago and traffic is always slow running thru it now. If you bypass around Chicago on 294 its usually ok expect during rush hours. On surface streets its hit or miss you never know what you will get. Some days its good some days it feels like you can walk faster