[1] The Dan Ryan, and its North Side counterpart the Kennedy Expressway, are the busiest roads in the entire state of Illinois.

Because of its width, the Dan Ryan is very popular with commuters who live south of the Loop, making the road prone to traffic jams during weekday rush hour.

Therefore, one who is traveling "west" on I-90/94 is actually driving north on the Dan Ryan as it passes through Chicago; I-90 continues northwest from the Kennedy split, while I-94 runs north–south until the Marquette Interchange in Milwaukee.

[citation needed] Four miles of continuous high-rise housing projects (Stateway Gardens and the Robert Taylor Homes) formerly ran parallel to the expressway on its eastern side from Cermak Road south to Garfield Boulevard.

Chicago pioneered the location of rapid transit line in expressway medians, a practice that has since been followed in several other cities, such as Toronto, and Pasadena.

It was named after the recently deceased Dan Ryan, Jr., who was President of the Cook County Board of Commissioners who had worked to accelerate construction of Chicago-area expressways.