Have your say on notorious bottleneck

Chicago's Circle Interchange often is more parking lot than expressway as more than 300,000 vehicles a day shoehorn into outdated infrastructure during rush hours.

The state hopes to improve the chronic congestion by hiring engineering consultants to study the chokepoint, and on Thursday the public is invited to comment on some of the conceptual designs. An Illinois Department of Transportation open house is set for 4 to 7 p.m. Thursday at the Marriott Chicago on the University of Illinois Chicago campus, 625 S. Ashland Ave., Chicago.

The interchange connects the Dan Ryan, Kennedy and Eisenhower expressways along with Congress Parkway. Built in the 1950s and 1960s, it delays the average vehicle about 10 minutes a day and earned the dubious title of the nation's worst bottleneck in 2010 by the Federal Highway Administration.

Improving the situation “is a big problem,” Northwestern University transportation expert Joseph Schofer said. “It's hard to imagine making a radical change in a situation like that.”

In addition to commuters getting around the city and suburbs, trucks make up a significant portion of Circle Interchange traffic. Nearly one in six vehicles using it is a truck, and many of those are hauling freight to and from O'Hare International Airport, according to IDOT.

Schofer, a transportation and civil engineering professor, noted that as truck tolls have increased on Illinois tollways, there's been a corresponding shift onto the freeways in the region. That becomes an issue when trucks that ideally should be using the Tri-State Tollway to circle around Chicago instead travel through the city using the Circle Interchange.

“One might step back and say — is there a more successful way to manage traffic flow on the (highway) network to get what we want out of it?” Schofer said. “Are there incentives for through vehicles using the tollway or disincentives if they want to come through town? It's not a particularly easy problem to solve without tearing up the whole system.”

The state in April hired consultants AECOM and TranSystems at a cost of $40 million to design interchange improvements, evaluate costs and come up with a time frame for the work. The study will take two years.