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Chicago Unravels Vexing Traffic Knot
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Aerial view Chicago's Circle Interchange
This fall the Illinois Department of Transportation is expected to begin work on a $420-million overhaul of Chicago’s Circle Interchange, including adding new lanes and rebuilding and expanding congested ramps. The interchange currently is jammed with more than 300,000 vehicles a day. Illinois Department of Transportation

A nightmarish intersection of several significant highways just west of Chicago’s Loop will be reconstructed for the first time in nearly 60 years, and the improvements will benefit both commuter and freight traffic.

April 30, 2013—Chicago’s Circle Interchange, which is just west of the Loop, is a mess.

Formed by the junction of three highways—the Kennedy Expressway to the north, the Dan Ryan Expressway to the south, and the Eisenhower Expressway to the west—the interchange handles more than 300,000 vehicles a day. (The Kennedy and Dan Ryan expressways form part of the interstate highways 90 and 94.) At peak hours commute speeds can slow to a crawl of 7 mph.

What is more, according to the American Transportation Research Institute and the Federal Highway Administration, the interchange is the country’s most congested bottleneck among freeways that are critical to the nation’s freight system. More than 30,000 trucks navigate the interchange every day. There are more than 1,110 crashes a year. The interchange, as a video on its official website notes, “operates in breakdown conditions for most of the day.”

But, finally, the aging interchange is about to be remade. Last month, the Illinois Department of Transportation (IDOT) received the go-ahead from Governor Pat Quinn to move forward on a $420-million reconstruction project. Built nearly 60 years ago, the interchange was designed for smaller traffic volumes, and some of its design elements are considered substandard today, for example, the insufficient number of lanes and the excessively steep grades. No major work has been done on the interchange since it was built.

“The intent is to really improve this centerpiece of infrastructure for the Chicagoland area and to start piecing together a regional vision for improving the Midwest transportation network,” says John Baczek, IDOT’s project and environmental studies section chief.

The project also recently received a badly needed boost from the Chicago Metropolitan Agency for Planning, the official regional planning organization. Last month the agency amended its 2010 long-range regional plan, GO TO 2040, to include the Circle Interchange overhaul. 

Another aerial view of the Circle Interchange

The Circle Interchange, just west of downtown Chicago, marks the
complicated junction where three major highways intersect.
Outside routine maintenance, no major work has been done on
interchange since it was built nearly 60 years ago. Illinois
Department of Transportation

“The state and IDOT looked at the need to modernize that interchange and recognized that putting a Band-Aid was not cost effective in the long run,” says Tom Garritano, the communications director for the Chicago Metropolitan Agency for Planning.

The project is expected to get under way this fall. Crews will be doing preparatory work for the first few years, including moving utilities and replacing bridges. The construction of the interchange itself will follow, and work should be finished by the end of the decade.

At present, as the Kennedy and Dan Ryan expressways enter the interchange, they narrow in both directions from five lanes to three, creating serious backups. The reconstruction will add a fourth lane in each direction for about three-fourths of a mile and leave additional space for a possible fifth lane, which would probably be some kind of managed toll lane.

Moreover, several of the congested ramps will be redesigned and rebuilt. Some ramps handle as many as 30,000 cars and trucks a day. Single-lane ramps cause congestion because on the approach to the interchange drivers either face multiple decision points or jockey for position, sometimes amidst a thicket of other ramps to nearby streets. Drivers will frequently try to avoid long queues as a lane backs up and then weave, or “cheat,” back into that lane. The steep grades of some of the ramps also pose a problem. During inclement weather in particular, Baczek says, the congestion is so heavy that cars and trucks get stuck on the ramps, forcing IDOT to send out tow trucks to rescue them.

In the case of the ramp that leads from northbound Dan Ryan to westbound Eisenhower, a new ramp will have to be constructed above the existing one because space is at such a premium; this will necessitate a longer ramp to make the grade more manageable. (Most of the ramps will be rebuilt at their current elevations.)

The interchange is situated within a dense urban fabric that includes a large business district, a major university and medical center, and residential neighborhoods. Many of the neighboring buildings are more than 100 years old, and there’s a complex network of bridges, ramps, and overpasses to consider. Crews will also have to be cognizant of two elevated tracks for the Chicago Transit Authority train system that extend through a pair of 15 ft wide tunnels directly below the interchange. (The trains emerge to the west of the interchange and run along the median of the Eisenhower as it heads west out of the city.)

As if that weren’t enough, there’s also a complex of water tunnels that carry between 60 and 180 mgd of water to and from a nearby pumping station, as well as abandoned water tunnels that can still be filled with water at times. Baczek says IDOT is “trying to identify and map all these constraints that make designing the interchange a complex challenge. You can’t put foundations through these pipes.” The abandoned water tunnels will have to be “bulkheaded,” he says—that is, filled with gravel, rock, and concrete—to prevent damage during construction.

Rendering of the pedestrian-only Peoria Street bridge

As part of the reconstruction of the Circle Interchange near
downtown Chicago, the pedestrian-only Peoria Street bridge will
be rebuilt and enhanced to make it more inviting for pedestrians
and cyclists. Illinois Department of Transportation

The project will affect nearly a dozen side streets, and the aesthetic enhancements planned include street benches, landscaping, decorative lighting, and new railings. Side streets will be reconfigured to provide more space for pedestrians and cyclists, and a pedestrian bridge at nearby Peoria Street will be improved. Feedback from residents and other stakeholders dictated a design that would be aesthetically appealing by virtue of its simplicity. “The message was pretty simple,” says Baczek. “Don’t overdesign it. Don’t make something too intricate.”

According to Baczek, the project will create 5,000 local jobs. It will also reduce carbon dioxide emissions from 120,000 metric tons per year to 80,000 metric tons by 2040. Planners expect a 50 percent reduction in delays, which will save drivers $185 million a year in lost time and cut gasoline consumption by 1.6 million gal.

In a time of shrinking federal and state budgets, it’s difficult for cities to add lane miles. Even in the City of the Big Shoulders, major capital projects have to be very carefully determined. “It definitely does increase pressure to make sure the current system is in a state of good repair, as opposed to expanding it,” says Garritano. “In the past many regions have been too focused on expanding and not focused on maintaining their system.”


 

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