Diverging Diamond Opening at I-88, Illinois 59

The Illinois Department of Transportation was joined by the Illinois Tollway and local officials Friday to announce that the new diverging diamond-style interchange at Illinois 59 and the Reagan Memorial Tollway (Interstate 88), in Naperville, will open in advance of the morning rush hour on Monday, Sept. 21, according to a release from IDOT. The interchange, the first of its kind in the Chicago area, incorporates a modern design that will improve traffic flow and safety throughout the area.

“The new interchange design might seem a little different at first, but I am confident that motorists will quickly see the benefits,” Illinois Transportation Secretary Randy Blankenhorn said. “This project is a great example of the type of innovation that the Illinois Department of Transportation is looking to embrace far into the future.”

Diverging diamond interchanges have been used successfully in other parts of the country by essentially routing traffic to the opposite side of the road and eliminating left turns across traffic. They have helped to cut the number of accidents in half in some locations. The design also will accommodate pedestrians and bicyclists by guiding them through the center of the interchange on a shared, multi-use path.

A video of how the interchange works can be viewed by visiting IDOT’s YouTube channel or by clicking here.

“The diverging diamond interchange is designed to improve travel at an interchange that serves more than 40,000 Tollway customers a day – some of the highest traffic volumes we see on our system,” said Illinois Tollway Executive Director Greg Bedalov. “This modern, new interchange will provide safer, faster and more efficient access to and from I-88 for Tollway customers.”

The interchange between Illinois 59 and the Reagan was chosen for the first diverging diamond design in the Chicago area due to the high traffic volumes making left turns. An average of 182,000 vehicles pass through the interchange each day. The first diverging diamond interchange in Illinois opened this summer at Interstate 57 and Illinois 13 in Marion. The Illinois Tollway currently has one under construction at Elmhurst Road and the Jane Addams Memorial Tollway (Interstate 90).

Construction of the new interchange at Illinois 59 and the Reagan started in 2013, part of the larger reconstruction and widening of Illinois 59 through Aurora and Naperville. Illinois 59 over the tollway will remain two lanes in each direction until mid-October, when an additional lane in each direction will be complete. Three lanes also will open on Illinois 59 between Diehl Road and North Aurora Avenue in mid-October. The entire $90 million project will be complete when all lanes open between North Aurora Avenue and New York Street/Aurora Avenue in early November.

Click here for more information and background on the larger Illinois 59 project.