A new diverging diamond interchange opened Monday at I-55 and Route 59 in Will County.
Courtesy of IDOT.
Notorious for its dysfunctional layout, the interchange of I-55 and Route 59 in Will County emerged with a makeover Monday.
Illinois Department of Transportation leaders unveiled a new diverging diamond design they predict will expedite travel for drivers on the interstate and local roads.
The $93.5 million interchange near Joliet is IDOT’s fourth diverging diamond project in the metro region, engineers said at a ribbon-cutting ceremony.
IDOT officials noted some elements of the project are still being completed and urged drivers to keep an eye out for work zones until substantial completion in late October.
“The modern design is a proven solution to improve safety and traffic flow in a busy area like where we are today,” IDOT Secretary Omer Osman said.
The original interchange had partial access, meaning northbound I-55 drivers could only exit north on Route 59, not south. Southbound Route 59 drivers could only go south on I-55.
“There was just one bridge. You didn’t have the twin bridges you’re looking at today,” Osman said.
In addition to the full interchange, IDOT crews added auxiliary lanes on I-55 between routes 59 and 52 to provide more capacity. Sidewalks and trails also were part of the project.
The interchange dovetails with Rock Run Collection, a major Will County development that will include housing, retail, restaurants, offices, and the relocated Hollywood Casino Joliet.
“This project will better connect the people of Will County to the exciting developments taking place in the area,” U.S. Sen. Dick Durbin said.
Illinois Department of Transportation Secretary Omer Osman, left, talks with U.S. Sen. Dick Durbin Monday near the site of a new interchange at I-55 and Route 59. Lt. Gov. Juliana Stratton is seated to the right.
Marni Pyke/mpyke@dailyherald.com
Other IDOT diverging diamond interchanges are located at I-55 and Weber Road, and I-80 and Houbolt Road in Will County; I-88 and Route 59 in Naperville; and in downstate Marion.
IDOT also is building one at I-39 and Route 20 in the Rockford area.
A Illinois tollway DDI is located at Elmhurst Road and I-90 in Des Plaines.
A diverging diamond has a smaller footprint than conventional cloverleafs and is cheaper to build.
Essentially, it briefly shifts traffic into opposite lanes using signals on bridges or underpasses so vehicles can turn left onto the highway without facing oncoming cars. Then, traffic is routed back to the right side of the road.